FU::Pg: Rename q() and Q() to sql() and SQL()

Because this easily confuses syntax highlighters and some humans with
the q// string syntax. Also for consistency with the 'fu->sql()'
aliases.

The old names are still available as alias.

FU/DebugImpl.pm

@@ -283,7 +283,7 @@ my @sections = (
 
     pgst => sub {
         return () if !$FU::DB;
-        my $lst = eval { $FU::DB->q(
+        my $lst = eval { $FU::DB->sql(
             'SELECT generic_plans + custom_plans, statement FROM pg_prepared_statements ORDER BY generic_plans + custom_plans DESC, statement'
         )->cache(0)->alla } || do { warn "Unable to collect prepared statement list: $@"; return () };
         return () if !@$lst;