Improve some error wording with multirange type parsing
Braces were referred in some error messages as only brackets (not curly
brackets or curly braces), which can be confusing as other types of
brackets could be used.
While on it, add one test to check after the case of junk characters
detected after a right brace.
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/
20210514.153153.
1814935914483287479.horikyota.ntt@gmail.com