Reject single line comments containing non-standard new line characers within Utf8JsonReader #27850

In particular, throw as invalid JSON if a single line comment contains U+2028 / U+2029 (i.e. Line separator, Paragraph separator) anywhere within it which JSON5 treats as valid line terminator sequences.

A single line comments ends on either carriage return, line feed, or both (\r\n). We do not support any other line terminator sequence.

This constraint does not apply to multi-line comments which only end with */.

cc @GrabYourPitchforks