Add *file_scoped_namespace_declaration* text

A few places that referenced namespace declarations didn't include the grammar production for *file_scoped_namespace_declaration* as well as *namespace_body*.

Author: BillWagner

standard/basic-concepts.md

@@ -245,7 +245,7 @@ A declaration defines a name in the ***declaration space*** to which the declara
 There are several different types of declaration spaces, as described in the following.
 
 - Within all compilation units of a program, *namespace_member_declaration*s with no enclosing *namespace_declaration* are members of a single combined declaration space called the ***global declaration space***.
-- Within all compilation units of a program, *compilation_unit_body*s that have the same fully qualified namespace name are members of a single combined declaration space.
+- Within all compilation units of a program, *namespace_member_declaration*s within *namespace_declaration*s that have the same fully qualified namespace name are members of a single combined declaration space. Per §14.3, this includes *file_scoped_namespace_declaration*s.
 - Each *compilation_unit* and *namespace_body* has an ***alias declaration space***. Each *extern_alias_directive* and *using_alias_directive* of the *compilation_unit* or *namespace_body* contributes a member to the alias declaration space ([§14.5.2](namespaces.md#1452-using-alias-directives)).
 - Each non-partial class, struct, or interface declaration creates a new declaration space. Each partial class, struct, or interface declaration contributes to a declaration space shared by all matching parts in the same program ([§16.2.4](structs.md#1624-partial-modifier)). Names are introduced into this declaration space through *class_member_declaration*s, *struct_member_declaration*s, *interface_member_declaration*s, or *type_parameter*s. Except for overloaded instance constructor declarations and static constructor declarations, a class, struct, or interface cannot contain a member declaration with the same name as the class, struct, or interface. A class, struct, or interface permits the declaration of overloaded methods and indexers. Furthermore, a class or struct permits the declaration of overloaded instance constructors and operators. For example, a class, struct, or interface may contain multiple method declarations with the same name, provided these method declarations differ in their signature ([§7.6](basic-concepts.md#76-signatures-and-overloading)). Note that base classes do not contribute to the declaration space of a class, and base interfaces do not contribute to the declaration space of an interface. Thus, a derived class or interface is allowed to declare a member with the same name as an inherited member. Such a member is said to ***hide*** the inherited member.
 - Each delegate declaration creates a new declaration space. Names are introduced into this declaration space through parameters (*fixed_parameter*s and *parameter_array*s) and *type_parameter*s.
@@ -772,9 +772,9 @@ The ***scope*** of a name is the region of program text within which it is possi
 > *Note*: It may not be possible to access the hidden outer name from the inner scope because there is no way of qualifying it, such as with type parameters on nested type declarations. *end note*
 
 - The scope of a namespace member declared by a *namespace_member_declaration* ([§14.6](namespaces.md#146-namespace-member-declarations)) with no enclosing *namespace_declaration* is the entire program text.
-- The scope of a namespace member declared by a *compilation_unit_body* whose fully qualified name is `N`, is every *compilation_unit_body* whose fully qualified name is `N` or starts with `N`, followed by a period.
-- The scope of a name defined by an *extern_alias_directive* ([§14.4](namespaces.md#144-extern-alias-directives)) extends over the *using_directive*s, *global_attributes*, and *compilation_unit_body* of its immediately containing *compilation_unit* or *namespace_body*. An *extern_alias_directive* does not contribute any new members to the underlying declaration space. In other words, an *extern_alias_directive* is not transitive, but, rather, affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs.
-- The scope of a name defined or imported by a *using_directive* ([§14.5](namespaces.md#145-using-directives)) extends over the *global_attributes* and *compilation_unit_body* of the *compilation_unit* or *namespace_body* in which the *using_directive* occurs. A *using_directive* may make zero or more namespace or type names available within a particular *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* but does not contribute any new members to the underlying declaration space. In other words, a *using_directive* is not transitive but rather affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs.
+- The scope of a namespace member declared by a *namespace_member_declaration* within a *namespace_declaration* whose fully qualified name is `N`, is the *namespace_body* of every *namespace_declaration* whose fully qualified name is `N` or starts with `N`, followed by a period. Per §14.3, *file_scoped_namespace_declaration*s are treated as equivalent *namespace_declaration*s for this rule.
+- The scope of a name defined by an *extern_alias_directive* ([§14.4](namespaces.md#144-extern-alias-directives)) extends over the *using_directive*s, *global_attributes*, and *compilation_unit_body* of its immediately containing *compilation_unit*, *namespace_body*, or *file_scoped_namespace_declaration*. An *extern_alias_directive* does not contribute any new members to the underlying declaration space. In other words, an *extern_alias_directive* is not transitive, but, rather, affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs.
+- The scope of a name defined or imported by a *using_directive* ([§14.5](namespaces.md#145-using-directives)) extends over the *global_attributes* and *compilation_unit_body* of the *compilation_unit*, *namespace_body*, or *file_scoped_namespace_declaration* in which the *using_directive* occurs. A *using_directive* may make zero or more namespace or type names available within a particular *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* but does not contribute any new members to the underlying declaration space. In other words, a *using_directive* is not transitive but rather affects only the *compilation_unit*, *namespace_body*, and *file_scoped_namespace_declaration* in which it occurs.
 - The scope of a type parameter declared by a *type_parameter_list* on a *class_declaration* ([§15.2](classes.md#152-class-declarations)) is the *class_base*, *type_parameter_constraints_clause*s, and *class_body* of that *class_declaration*.
     > *Note*: Unlike members of a class, this scope does not extend to derived classes. *end note*
 - The scope of a type parameter declared by a *type_parameter_list* on a *struct_declaration* ([§16.2](structs.md#162-struct-declarations)) is the *struct_interfaces*, *type_parameter_constraints_clause*s, and *struct_body* of that *struct_declaration*.