[clang-format] Fix documentation for FixNamespaceComments

[owenpan]

Summary

Fixes PR40409.

cfe/trunk/docs/ClangFormatStyleOptions.rst

**FixNamespaceComments** (``bool``)
   If ``true``, clang-format adds missing namespace end comments and
   fixes invalid existing ones.
 
   .. code-block:: c++
 
      true:                                  false:
      namespace a {                  vs.     namespace a {
      foo();                                 foo();
-     } // namespace a;                      }
+     } // namespace a                       }
 
 **ForEachMacros** (``std::vector<std::string>``)
   A vector of macros that should be interpreted as foreach loops
   instead of as function calls.
 
   These are expected to be macros of the form:
 
   .. code-block:: c++

cfe/trunk/include/clang/Format/Format.h

   bool ExperimentalAutoDetectBinPacking;
 
   /// If ``true``, clang-format adds missing namespace end comments and
   /// fixes invalid existing ones.
   /// \code
   ///    true:                                  false:
   ///    namespace a {                  vs.     namespace a {
   ///    foo();                                 foo();
-  ///    } // namespace a;                      }
+  ///    } // namespace a                       }
   /// \endcode
   bool FixNamespaceComments;
 
   /// A vector of macros that should be interpreted as foreach loops
   /// instead of as function calls.
   ///
   /// These are expected to be macros of the form:
   /// \code