pgsql: Apply code-reviewed version of for-scalar-list patch: mostly, - Mailing list pgsql-committers

Log Message:
-----------
Apply code-reviewed version of for-scalar-list patch: mostly, fixing
it to report reasonable errors in error cases.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        plpgsql.sgml (r1.85 -> r1.86)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml.diff?r1=1.85&r2=1.86)
    pgsql/src/pl/plpgsql/src:
        gram.y (r1.84 -> r1.85)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/gram.y.diff?r1=1.84&r2=1.85)
    pgsql/src/test/regress/expected:
        plpgsql.out (r1.41 -> r1.42)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/plpgsql.out.diff?r1=1.41&r2=1.42)
    pgsql/src/test/regress/sql:
        plpgsql.sql (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/plpgsql.sql.diff?r1=1.35&r2=1.36)