* UX: replace highlight vars in popup menu
* UX: replace highlight vars in autcomplete
* UX: replace highlight vars in menu-panel
* UX: update style guide
* UX: bulk replace highlight vars in various small appearances
**This PR creates a new core reusable component wraps a character counter around any input.**
The component accepts the arguments: `max` (the maximum character limit), `value` (the value of text to be monitored).
It can be used for example, like so:
```hbs
<CharCounter @max="50" @value={{this.charCounterContent}}>
<textarea
placeholder={{i18n "styleguide.sections.char_counter.placeholder"}}
{{on "input" (action (mut this.charCounterContent) value="target.value")}}
class="styleguide--char-counter"></textarea>
</CharCounter>
```
**This PR also:**
1. Applies this component to the chat plugins edit channel's *Edit Description** modal, thereby replacing the simple text area which provided no visual indication when text exceeded the max allowed characters.
2. Adds an example to the `/styleguide` route
In the past, the result of template compilation would be stored directly in `Ember.TEMPLATES`. Following the move to more modern ember-cli-based compilation, templates are now compiled to es6 modules. To handle forward/backwards compatibility during these changes we had logic in `discourse-boot` which would extract templates from the es6 modules and store them into the legacy-style `Ember.TEMPLATES` object.
This commit removes that shim, and updates our resolver to fetch templates directly from es6 modules. This is closer to how 'vanilla' Ember handles template resolution. We still have a lot of discourse-specific logic, but now it is centralised in one location and should be easier to understand and normalize in future.
This commit should not introduce any behaviour change.
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
