GFM meta-data parser mishandles missing EOL after last entry

If the last meta-data item is not followed by an EOL, the parser treats the last line as both a meta-data item and part of the body content.

This is not worth fixing on its own, but should be fixed as part of any other related fixes

Locate the GFM metadata parser and reproduce the case described: a final metadata entry without a trailing EOL. Check how that line is classified between metadata and body content; done means the final entry is parsed as metadata without also appearing in the body, with a regression test covering the missing EOL.

Written by the indexing model from the issue text.