Don't quote language name

It's been deprecated for ages according to Tom, and it breaks now given
the previous patch anyway.

Per buildfarm

contrib/citext/citext--1.0.sql

@@ -232,12 +232,12 @@ DEFAULT FOR TYPE citext USING hash AS
 CREATE FUNCTION citext_smaller(citext, citext)
 RETURNS citext
 AS 'MODULE_PATHNAME'
-LANGUAGE 'C' IMMUTABLE STRICT;
+LANGUAGE C IMMUTABLE STRICT;
 
 CREATE FUNCTION citext_larger(citext, citext)
 RETURNS citext
 AS 'MODULE_PATHNAME'
-LANGUAGE 'C' IMMUTABLE STRICT;
+LANGUAGE C IMMUTABLE STRICT;
 
 CREATE AGGREGATE min(citext)  (
     SFUNC = citext_smaller,