Turn parse_language into a method

Turn parse_language into a method

This changes parse_language into a method of parser_state.  This patch
was written by a script.

gdb/ChangeLog
2019-04-04  Tom Tromey  <tom@tromey.com>

	* rust-exp.y: Replace "parse_language" with method call.
	* p-exp.y:
	(yylex): Replace "parse_language" with method call.
	* m2-exp.y:
	(yylex): Replace "parse_language" with method call.
	* go-exp.y (classify_name): Replace "parse_language" with method
	call.
	* f-exp.y (yylex): Replace "parse_language" with method call.
	* d-exp.y (lex_one_token): Replace "parse_language" with method
	call.
	* c-exp.y:
	(lex_one_token, classify_name, yylex): Replace "parse_language"
	with method call.
	* ada-exp.y (find_primitive_type, type_char)
	(type_system_address): Replace "parse_language" with method call.