Fix "Unable to identify an operator =$" problem that occurred when pgsql

expressions were written without spaces between operators and operands.
Problem was that something like "if new.f1=new.f2 then" would be translated
to "if $1=$2 then", and the Postgres lexer would tokenize that the wrong
way.  Fix is to emit spaces around $paramno constructs to ensure they are
seen as separate tokens.

src/pl/plpgsql/src/gram.y

@@ -4,7 +4,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.7 1999/08/16 19:57:21 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.8 1999/11/28 22:02:17 tgl Exp $
  *
  *    This software is copyrighted by Jan Wieck - Hamburg.
  *