The reAttributeName regexp in parseMacroParameterAsAttribute was too
permissive, allowing single-character names like dollar sign followed by
colon. This caused values such as dollar-colon-slash-plugins-foo to be
mis-parsed as a named parameter dollar with value slash-plugins-foo.
Fix: when the separator is colon (legacy syntax), require the parameter
name to match [A-Za-z0-9-_]+ (same as the historic parseMacroParameter).
When the separator is equals (new-style dynamic parameters from #9055),
the wide character set is preserved so that names like double-dollar-one
continue to work.
Adds regression test Transclude/Procedures/Dollar/Param.
d977b0ac5c