* Tag sketch
* Drop objectAssign; already using Object.assign elsewhere
* Basic \gdef support
* Bug fix
* Finish \tag
* MathML numbers equations with <mlabeledtr>
* Fix flow bugs
* \gdef tests
* Add basic \tag tests
* Screenshot test for \tag
* \tag* test
* Add missing file
* Bug fix screenshot
* Major refactor
* Represent tag at top level of parse tree, requiring less hackery
* No more \@tag function; it was essentially just doing \text
* Wrap tag in group so e.g. ( and ) are formatted the same
* Add `feed` method to MacroExpander for multiple inputs (for tag)
* Bug fixes in buildHTML, makeTextRow, _getBuilt (for display mode)
* Remove excess <mrow> wrapper when unnecessary
* Update screenshot from tag being wrapped in group
* Add maxExpand limit
* Move test helpers into common modules
* helpers.js gets all the helper functions
* setup.js gets the common Jest setup (serializer, expect extensions)
* Exclude test from coverage testing
* @ylemkimon's comments: parsing -> building, settings || defaultSettings
* Default argument for settings
* Fix lint errors
* @ylemklemon's comment: use buildAndSetResult
* Use template literals
