Fix example for mustache in client-side-templates extension.

[airblast-dev]

Description

The unnecessary escape sequences were removed from the mustache full example as they broke the output.
The template key "UserID" was renamed to "UserId" as the test API uses "UserId". The old key name would result in a blank string as the keys wouldnt match.

Corresponding issue:
#2407

Testing

I have tested the changed example in the docs. It is working correctly.

Checklist

• I have read the contribution guidelines
• I have targeted this PR against the correct branch (master for website changes, dev for
  source changes)
• This is either a bugfix, a documentation update, or a new feature that has been explicitly
  approved via an issue
• I ran the test suite locally (npm run test) and verified that it succeeded

[airblast-dev]

There is one more thing that should be fixed. The jsbin example linked right under the example in the docs is really out of date, and also uses the incorrect key name "UserID" instead of "UserId". It would be really sweet if the jsbin example could be updated by one of the maintainers with the new example, or just remove the jsbin example altogether.

[alexpetros]

Thank you!