Make type prefix optional for enumeration and duration literals in URLs

4.01 Services MUST support Implicit cast from string to enum in URL. This allows the use of the string value of the enum in place of the full value, as in: $filter=Color eq 'Yellow' in addition to the existing $filter=Color eq ns.Color'Yellow'. Also apply to duration literals in URLs.

https://www.oasis-open.org/apps/org/workgroup/odata/download.php/59028/odata-v4.01-wd01-part1-protocol.docx https://www.oasis-open.org/apps/org/workgroup/odata/download.php/59029/odata-v4.01-wd01-part2-url-conventions.docx https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/4.01%20spec/ABNF/odata-abnf-construction-rules.txt