Make links in schema text/content clickable

[sujaypatil96]

The links that appear in schema element descriptions, etc. will now be clickable.

Fixes #682

[sujaypatil96]

To see a preview of how this works, look at the below pages:

• https://sujaypatil96.github.io/mixs/term_list/ (look in the description column)
• https://sujaypatil96.github.io/mixs/0001215/
• https://sujaypatil96.github.io/mixs/0001179/