EU marked by spellchecker despite being in dictionary

[anyllmarkevich]

Describe the bug
The word "EU" is marked as misspelled despite appearing in Harper's dictionary.

To Reproduce
Steps to reproduce the behavior:

1. Type "EU" in a text box that supports Harper.
2. See error

Expected behavior
EU stands for European Union and is correctly spelled (analogous to US, USA, etc).

Screenshots
Not applicable.

Platform
Harper core, Obsidian, etc.

Additional context
None.

[hippietrail]

This would almost certainly be part of the problems we have with all caps words especially when there is a variant in the dictionary with some other lettercasing. In this case there's Eu, which is the symbol for the element Europium.

Fortunately, there's a PR under development right now by a new contributor that addresses these problems: #2630