Also fix a linting error.

Continues to clear out any existing queued messages as before, but only changes the associated DOM if its Mathquill container also has focus.

The idea is to prevent potential ARIA alert collisions from multiple Mathquills.

Scope ARIA element to mathquill instance

Add back relative positioning that was lost in the merge with upstream:

https://github.com/desmosinc/mathquill/pull/164/files#diff-79e9660ce59c4876801ff9682357e9e842311c5794d68c8ac77e3bc5c235de0dL419

…ning

Fix overarrow positioning

Previously the Desmos fork purposefully removed the gray boxes for parens and square brackets which diverges from upstream's default. This change allows users to specify which delimiters are meant to be transparent instead.

Still somewhat crude, may need expansion later. Right now it accepts optional text followed by a paren, bracket, or curly brace as a space-separated string of values.

…-optionally-hide-bracket-rectangles

…acket-rectangles

Add quietEmptyDelimiters option

Add some comments

Add benchmark of time to select n characters

…ipt-expansion-option

Add "disableAutoSubstitutionInSubscripts" option