Develop the final formula widget

[lerongil]

In order to finalize the formula widget, we need to answer three questions:

• [x] What is the best way to ensure a user understands that the formula is interactive?

• [x] At what level does the user interact with the formula?

• [x] How does an educator use this with other formulas?

In order to answer this question, let's use the 2nd equation from the QV lesson as the base example:

[techtolentino]

Update to checkbox 1: The team decided to use a light underline for each interactive part of the formula. After several prototypes and discussion, we merged the update here - https://github.ibm.com/IBM-Q-Software/project-platypus/pull/52

Please note that this is currently being tested through our user testing sessions.

[techtolentino]

Update for checkbox 3:

Following the codebase convention from Mathigon, we've added documentation here

As @delapuente pointed out - this is a starting point. As we work towards elevating this work, we can revisit the documentation to see what the best way is, for presenting it.

From the content contribution side, however, we feel pretty good about having this as a foundation.