improve convention node on controller suffixes

Author: keithamus

docs/_guide/conventions.md

@@ -5,9 +5,9 @@ subtitle: Conventions
 
 Catalyst strives for convention over code. Here are a few conventions we recommend when writing Catalyst code:
 
-### Use `Element` or `Component` to suffix your controller class
+### Suffix your controllers consistently, for symmetry
 
-Built in HTML elements all extend from the `HTMLElement` constructor, and are all suffixed with `Element` (for example `HTMLElement`, `SVGElement`, `HTMLInputElement` and so on). Catalyst components can be suffixed with `Element`, `Component` or `Controller`. We think elements should behave as closely to the built-ins as possible, so we like to use `Element`, but the other suffixes might be useful for symettry with other server side comoponent frameworks such as [ViewComponent](https://viewcomponent.org/).
+Catalyst components can be suffixed with `Element`, `Component` or `Controller`. We think elements should behave as closely to the built-ins as possible, so we like to use `Element` (existing elements do this, for example `HTMLDivElement`, `SVGElement`). If you're using a server side comoponent framework such as [ViewComponent](https://viewcomponent.org/), it's probably better to suffix `Component` for symmetry with that component framework.
 
 ```typescript
 @controller