"Call super? Not necessary." is misleading - may affect mixins

[jrencz]

In Article https://lit.dev/docs/components/lifecycle/#content next to most described lifecycle callbacks there's a "Call super? Not Necessary" info.

lit.dev/packages/lit-dev-content/site/docs/v3/components/lifecycle.md

Line 221 in 03ee5b7

| Call super? | Not necessary. |

(and others like this one)

I think those are misleading - it's only true unless component uses mixins or if neither mixin in chain implements lifecycle callbacks, which If I understand

lit.dev/packages/lit-dev-content/site/docs/v3/composition/mixins.md

Lines 85 to 91 in 03ee5b7

	## Creating mixins for LitElement
	Mixins applied to LitElement can implement or override any of the standard
	[custom element lifecycle](/docs/v3/components/lifecycle/#custom-element-lifecycle)
	callbacks like the `constructor()` or `connectedCallback()`, as well as any of
	the [reactive update lifecycle](/docs/v3/components/lifecycle/#reactive-update-cycle)
	callbacks like `render()` or `updated()`.

is OK for mixins to do.

Before I file a PR to adjust I want to as for conformation if I understand the problem correctly