Support \underline in text mode

[edemaine]

Fix #1158 with a one-line change. I could not find any other "long accents" that are supposed to work in text mode, but let me know if you find any!

Screenshot:

Comparison to LaTeX:

[codecov]

Codecov Report

Merging #1159 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1159   +/-   ##
=======================================
  Coverage   79.37%   79.37%           
=======================================
  Files          59       59           
  Lines        3865     3865           
  Branches      648      648           
=======================================
  Hits         3068     3068           
  Misses        662      662           
  Partials      135      135

Impacted Files	Coverage Δ
src/functions/underline.js	8.33% <ø> (ø)	⬆️

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[ry-randall]

Glad this was a simple/quick fix!

[ry-randall]

@edemaine Meant to mention prior to approving. Perhaps we'd want to add a test for this? Might be able to add to the existing "Text" screenshot.

Tests

[edemaine]

I added a simple test to the LowerAccent one which currently tests \underline. Let me know what you think!

[ry-randall]

Thanks for the test. Glad this was a simple fix!