* Correct list's "find" and "get" blocks help.
Both blocks were using the same help URL.
Two unrelated results of recompiling messages:
* Allow unwanted 'qqq' messages to be reverted.
* 'constants.json' is unchanged, but sorted.
Also improve python json dumping.
* fix: loading messages in the browser
* chore: fix comment
* fix: change unwrapped message files to write to a new object, rather than Blockly.Msg
* fix: fixup exports
* fix: PR comments
* fix: change to use for-in loop
* fix: ES6 compatibility and formatting
