I noticed a minor inconsistency with the search_path separator used in the default configuration.
The schemas of any search_path set using `SET search_path TO...` are separated by ", " (comma, space), while the default value is only separated by "," (comma).
The attached patch against master changes the separator of the default value to be consistent with the usual comma-space separators, and updates the documentation of `SHOW search_path;` accordingly.
This massive three-byte change passes all 144 tests of make check.
