doesn't recognize Umlauts

[tvogt]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Reproduced the problem in Safe Mode: https://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
  • Followed all applicable steps in the debugging guide: https://flight-manual.atom.io/hacking-atom/sections/debugging/
  • Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
  • Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

Steps to Reproduce

1. Type a bunch of stuff with words using german Umlauts (äöüß) or - probably - any other kind of non-ASCII letters. For example, use "Tannenbäume" (christmas trees)
2. Type something else and start writing "Tanne..."
3. Autocomplete should activate, but instead of offering "Tannenbäume", it only offers "Tannenb" - it stops at the Umlaut, probably thinking its the end of the word or something.

Expected behavior:

recommend "Tannenbäume" as auto-completion

Actual behavior:

recommends "Tannenb"

Reproduces how often:

Always

Versions

MacOS: 10.14.6
Atom : 1.37.0
Electron: 2.0.18
Chrome : 61.0.3163.100
Node : 8.9.3