XML (Debug): Fix incorrect DetectChar rule

Summary:
The fix is to simply remove the parts of the char that were
ignored anyways. Whether this is the correct patch is up for
discussion - but since noone complained for years, this is
possibly not a big issue anyways. And: the XML (Debug) file
does not have any extension nor mimetype, so we can safely
say essentially noone is using this...

Fixes:
checkSingleChars: xmldebug.xml" line 130 'char' must contain exactly one char: "\"(\\s+|$)"
checkSingleChars: xmldebug.xml" line 135 'char' must contain exactly one char: "'(\\s+|$)"
checkSingleChars: xmldebug.xml" line 374 'char' must contain exactly one char: "\"(\\s+|$)"
checkSingleChars: xmldebug.xml" line 379 'char' must contain exactly one char: "'(\\s+|$)"
checkSingleChars: xmldebug.xml" line 416 'char' must contain exactly one char: "\"(\\s+|$)"
checkSingleChars: xmldebug.xml" line 421 'char' must contain exactly one char: "'(\\s+|$)"
checkSingleChars: xmldebug.xml" line 468 'char' must contain exactly one char: "\"(\\s+|$)"
checkSingleChars: xmldebug.xml" line 473 'char' must contain exactly one char: "'(\\s+|$)"

Test Plan: make test

Reviewers: vkrause

Reviewed By: vkrause

Subscribers: Frameworks

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D9369