Rename transformRelOptions()'s "namspace" parameter to "nameSpace".

Rename transformRelOptions()'s "namspace" parameter to "nameSpace".

The name "namspace" looks like a typo, but it was presumably meant
to avoid using the "namespace" C++ keyword.  This commit renames
the parameter to "nameSpace" to prevent future confusion while
still avoiding the keyword.

Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://postgr.es/m/aJJxpfsDfiQ1VbJ5%40nathan