Look into making combining accents work in Chrome

There is a problem with knowing what characters to use for accents. See https://mathfonts.github.io/math-accents for how they render in a browser. For Chrome, you can see that the combining characters are not centered properly. Appendix B3 lists some equivalences, but that is currently not referenced in the spec

@eerii: can that be fixed in Chrome so that the spec can say "use the combining characters" for accents?

Appendix B3 is the minimal list that should be supported if they can be supported. For reference, there are the ranges where math-relevant combining characters live in Unicode:

• Combining Diacritical Marks: U+0300–U+036F
  The most common block, containing standard European diacritics (acute, grave, circumflex, etc.) and IPA extensions.  

• Combining Diacritical Marks for Symbols: U+20D0–U+20FF
  Contains combining marks for mathematical and technical symbols, such as enclosing circles, squares, or arrows.

There is also a question about which characters should stretch, but we should resolve this first before moving on to stretchy chars.

Start with the math-accents rendering page and compare Chrome’s combining-accent positioning against the equivalences in MathML Core Appendix B3. Determine which listed combining characters are supported and what the spec can state; done means the supported minimal list and any required Chrome change are clearly identified before addressing stretchy characters.