Fix position of inline help icon caused by changes in #1350

[dpvc]

This PR fixes a regression in the positioning of the help icon for in-line math expression caused by the changes in #1350. The positioning in that commit cause in-line help icons to not be attached to the in-line expression, but to the nearest block-level parent.

The fix is to use the old CSS for inline math and move the new CSS to the [display="true"] selector.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.48%. Comparing base (af44f98) to head (d8d8fc4).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1400   +/-   ##
========================================
  Coverage    86.48%   86.48%           
========================================
  Files          340      340           
  Lines        85818    85818           
  Branches      4815     4815           
========================================
  Hits         74218    74218           
  Misses       11577    11577           
  Partials        23       23           

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[zorkow]

From what I can see (sample expression $\sqrt{x}^2$ the info icon does now no longer ascend beyond the line, e.g, is on the same height as the 2 rather than in its top right hand corner (if that makes sense).
Looks better!