tidy: add missing trailing newline

Author: Mrmaxmeier

src/doc/unstable-book/src/compiler-flags/embed-source.md

@@ -7,4 +7,4 @@ object debug info section. It takes one of the following values:
 * `n`, `no`, `off`, `false` or no value: omit source code from debug info (the default).
 
 `-C embed-source` requires DWARFv5 and is only supported with the LLVM backend.
-Use `-Z dwarf-version=5` to control the compiler's DWARF target version.
+Use `-Z dwarf-version=5` to control the compiler's DWARF target version.