Properly escape $-usage with span-tags

[ichistmeinname]

Summary

On May 19th GitHub Markdown started to support math-mode using $-signs which breaks the documentation; see usage here. Span-tags are the way to fix a direct usage of $ in text mode.

[mattermod]

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[ichistmeinname]

/check-cla

[codecov-commenter]

Codecov Report

Merging #198 (cd5637f) into master (3282131) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #198   +/-   ##
=======================================
  Coverage   40.79%   40.79%           
=======================================
  Files           6        6           
  Lines         679      679           
=======================================
  Hits          277      277           
  Misses        382      382           
  Partials       20       20           

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[mattermod]

This PR has been automatically labelled "stale" because it hasn't had recent activity.
A core team member will check in on the status of the PR to help with questions.
Thank you for your contribution!

[hanzei]

/check-cla

[hanzei]

Thanks for the fix 👍