[Feature] Support AMS numbering rule for math equations

[silencial]

For now the Auto Numbering Math Equations option in Typora is using MathJax 'all' tagging option. Having another option as 'ams' tagging will be useful too, check MathJax doc

[orsonhart]

This would be a very useful feature, as at the moment there is a desync between Typora and other Markdown editors (which use the 'ams' tagging option)

[abnerlee]

supported in 1.4.4