docs: add mustaches vs v-html example

[phanan]

When translating this part of the guide into Vietnamese I felt an example would explain the differences between double-mustache syntax and v-html directive much more clearly. If the PR is merged, we'll have something like this:

Does this make sense?

[phanan]

Btw I notice we have a lot of examples at the beginning and fewer and fewer of them (feels like we're "getting tired") deeper into the guide.

[chrisvfritz]

Great improvement! Thanks. 😄

Btw I notice we have a lot of examples at the beginning and fewer and fewer of them (feels like we're "getting tired") deeper into the guide.

Please do open issues or PRs as you notice more missing examples. I'm currently in the process of completely revamping components, so don't worry about that for now - but anything else would be very useful.