gdb: Convert language la_get_symbol_name_matcher field to a method

This commit changes the language_data::la_get_symbol_name_matcher
function pointer member variable into a member function of
language_defn.

There should be no user visible changes after this commit.

Before this commit access to the la_get_symbol_name_matcher function
pointer was through the get_symbol_name_matcher function, which looked
something like this (is pseudo-code):

  <return-type>
  get_symbol_name_matcher (language_defn *lang, <other args>)
  {
    if (current_language == ada)
      current_language->la_get_symbol_name_matcher (<other args>);
    else
      lang->la_get_symbol_name_matcher (<other args>);
  }

In this commit I moved the get_symbol_name_matcher as a non-virtual
function in the language_defn base class, I then add a new virtual
method that is only used from within get_symbol_name_matcher, this can
then be overridden by specific languages as needed.  So we now have:

  class language_defn
  {
    <return-type> get_symbol_name_matcher (<args>)
    {
      if (current_language == ada)
        return current_language->get_symbol_name_matcher_inner (<args>);
      else
        return this->get_symbol_name_matcher_inner (<args>);
    }

    virtual <return-type> get_symbol_name_matcher_inner (<args>)
    {
        ....
    }
  }

gdb/ChangeLog:

	* ada-lang.c (ada_get_symbol_name_matcher): Update header comment.
	(ada_language_data): Delete la_get_symbol_name_matcher
	initializer.
	(language_defn::get_symbol_name_matcher_inner): New member
	function.
	* c-lang.c (c_language_data): Delete la_get_symbol_name_matcher
	initializer.
	(cplus_language_data): Likewise.
	(cplus_language::get_symbol_name_matcher_inner): New member
	function.
	(asm_language_data): Delete la_get_symbol_name_matcher initializer.
	(minimal_language_data): Likewise.
	* cp-support.h (cp_get_symbol_name_matcher): Update header comment.
	* d-lang.c (d_language_data): Delete la_get_symbol_name_matcher
	initializer.
	* dictionary.c (iter_match_first_hashed): Update call to
	get_symbol_name_matcher.
	(iter_match_next_hashed): Likewise.
	(iter_match_next_linear): Likewise.
	* dwarf2/read.c (dw2_expand_symtabs_matching_symbol): Likewise.
	* f-lang.c (f_language_data): Delete la_get_symbol_name_matcher
	initializer.
	(f_language::get_symbol_name_matcher_inner): New member function.
	* go-lang.c (go_language_data): Delete la_get_symbol_name_matcher
	initializer.
	* language.c (default_symbol_name_matcher): Update header comment,
	make static.
	(language_defn::get_symbol_name_matcher): New definition.
	(language_defn::get_symbol_name_matcher_inner): Likewise.
	(get_symbol_name_matcher): Delete.
	(unknown_language_data): Delete la_get_symbol_name_matcher
	initializer.
	(auto_language_data): Likewise.
	* language.h (language_data): Delete la_get_symbol_name_matcher
	field.
	(language_defn::get_symbol_name_matcher): New member function.
	(language_defn::get_symbol_name_matcher_inner): Likewise.
	(default_symbol_name_matcher): Delete declaration.
	* linespec.c (find_methods): Update call to
	get_symbol_name_matcher.
	* m2-lang.c (m2_language_data): Delete la_get_symbol_name_matcher
	initializer.
	* minsyms.c (lookup_minimal_symbol): Update call to
	get_symbol_name_matcher.
	(iterate_over_minimal_symbols): Likewise.
	* objc-lang.c (objc_language_data): Delete
	la_get_symbol_name_matcher initializer.
	* opencl-lang.c (opencl_language_data): Likewise.
	* p-lang.c (pascal_language_data): Likewise.
	* psymtab.c (psymbol_name_matches): Update call to
	get_symbol_name_matcher.
	* rust-lang.c (rust_language_data): Delete
	la_get_symbol_name_matcher initializer.
	* symtab.c (symbol_matches_search_name): Update call to
	get_symbol_name_matcher.
	(compare_symbol_name): Likewise.

gdb/d-lang.c

@@ -160,7 +160,6 @@ extern const struct language_data d_language_data =
   default_word_break_characters,
   default_collect_symbol_completion_matches,
   c_watch_location_expression,
-  NULL,				/* la_get_symbol_name_matcher */
   &default_varobj_ops,
   c_is_string_type_p,
   "{...}"			/* la_struct_too_deep_ellipsis */