From a very early time, we had a few things that Djblets monkey-patched into the standard String class for JS code. This change gets rid of the use of those in the RB codebase: * `String.trim()` is a standard-library method that does what our `String.strip()` method did. * `_.escape()` and `_.unescape()` do what our `String.htmlEncode()` and `String.htmlDecode()` methods did (plus are slightly more complete). * `String.stripTags()` was only used in one place, which was already doing some regex transformations, so I've just moved the implementation of that into where it's used. We don't use that option at all, though, so perhaps we should just remove it from the inline editor too. * `String.truncate()` wasn't used anywhere. Testing Done: Ran js-tests.