Rewrite exercise to mix number types and simplify
Add hints
Multiple question types
Hint for second question type
Fix data-fallback="0"

Silly jQuery...

Auditors: emily
extraneous_solutions: Use set the simpler way

set already doesn't care about order, so just use it as it was intended.

Test Plan:
Answered extraneous_solutions.html?seed=29&problem=ignore-extraneous with 7.

Auditors: peter
Remove spurious paren.

Auditors: alpert

Test Plan:
make i18n (in the main codebase)
Update update title tag script

Now it doesn't totally die on missing exercise files.

Auditors: eater
Update title tags
Change scratchpad bounds to be wider

Also tweaked the spacing a bit so it looks nicer.

Before:
{F4418}

After:
{F4419}

Auditors: alex
Small improvements to scratchpad drawing

Apart from some general code cleanup, this makes it so that all curves are drawn with bezier quad curves to be smoother and dragging the pen outside the scratchpad and back inside looks better.

Auditors: alex
Minor rewrite of  hints
Make suggested changes
Merge pull request #62760 from petercollingridge/add-rat-num

Rewrite exercise to mix number types and simplify
Create exercise
Simplify exercise
Term.regex() can be treated by RationalExpression.regex()
Update rational expression unit test
Remove unnecessary extras to regex
Remove unnecessary extras to regex