Unicode TR#18 defines \w as a shorthand for

\p{alpha}
\p{gc=Mark}
\p{digit}
\p{gc=Connector_Punctuation}

which would include all marks. We should recursively check whether we
follow the recommendation (e.g. \p{alpha} refers to all character having
the Alphabetic derived core property, which is Lu+Ll+Lt+Lm+Lo+Nl +
Other_Alphabetic, where Other_Alphabetic is a selected list of
additional character - all from Mn/Mc)