Ensure same event naming and add to convention definition

[bddckr]

We use both Started/Stopped and Begun/Ended (and maybe even combinations of those) for event names.

We should change it so the naming is the same everywhere and then update our convention documentation to list this.

[thestonefox]

I think there may actually be a case for both

https://dictionary.cambridge.org/grammar/british-grammar/begin-or-start

granted we need to make sure existing uses adhere to these grammatical rules