Buffer Source Completion: diacritic characters are ignored

[xeluxee]

Is your feature request related to a problem? Please describe.

Diacritics characters (such as à, ü, ô) are ignored by buffer completion source. That problem is evident especially when editing (for example) tex files, where buffer words completion is really useful.
These characters are considered word separators, like spaces.

Describe the solution you'd like

Diacritic characters should be included in words.

Describe alternatives you've considered

Diacritic characters aren't ignored by other completion engines, such as https://github.com/ycm-core/YouCompleteMe and https://github.com/neoclide/coc.nvim

Additional context

Nothing to add

[Dmytro Meleshko]

Try using \k\+ for the default_pattern as described in #495

#495 (comment)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.