* added support for \boldsymbol
* added \boldsymbol tests
* added \boldsymbol screenshots
* added \bm, snapshot, updated screenshots
* updated snapshot for \boldsymbol
* properly display \imath and 2 in boldsymbol
* implemented \boldsymbol for +
* fix typo, remove boldsymbolLetters hardcode
* make comment about using Main-Bold more general
* fixed trailing space CI error
