MrowNormalizer - fenced expression format

[jakubadler]

Apart from removing redundant mrow elements, MrowNormalizer also adds mrow to transform detected fenced expressions to the form:

<mrow><mo>(</mo><mrow> ... </mrow><mo>)</mo></mrow>

I'm not sure what should be preferred in case when this format breaks the rules for mrow minimizing (only one element in inner mrow, etc.) Should the redundant elements be removed or should the exact format be kept?

[formanek]

Mrows (added or removed) near parentheses should be consistent with MfencedReplacer (when configured accordingly) - canonicalized result should be the same for the semantically same for formula expressed using mfenced tag or expression with parentheses around (with various mrows inside and outside), which is prefered to general mrow minimizing rules.

However, MfencedReplacer does not add inner mrow if only one element is present so it is a bug if MrowNormalizer does that. (Note that canonicalizer can also be configured not to add inner or outer mrows at all.)