C#: Address review comments.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/exprs/Assignment.qll

@@ -144,7 +144,7 @@ class AssignSubExpr extends AssignArithmeticExpr, SubOperation, @assign_sub_expr
 }
 
 /**
- * An multiplication assignment expression, for example `x *= y`.
+ * A multiplication assignment expression, for example `x *= y`.
  */
 class AssignMulExpr extends AssignArithmeticExpr, MulOperation, @assign_mul_expr {
   override string getOperator() { result = "*=" }

csharp/ql/lib/semmle/code/csharp/exprs/LogicalOperation.qll

@@ -31,7 +31,7 @@ class LogicalNotExpr extends UnaryLogicalOperation, @log_not_expr {
 
 /**
  * A binary logical operation. Either a logical 'and' (`LogicalAndExpr`),
- * a logical 'or' (`LogicalAndExpr`), or a null-coalescing operation
+ * a logical 'or' (`LogicalOrExpr`), or a null-coalescing operation
  * (`NullCoalescingOperation`).
  */
 class BinaryLogicalOperation extends LogicalOperation, BinaryOperation, @bin_log_operation {