docs: Make license section use American spelling

[validcube]

This is on my todolist for a very long time, I'll propagate this PR to other revanced repositories after the PR is merged within N+2 days unless requested change.

The license section uses British spelling of the word license ("licence"), which isn't intentional because ReVanced uses American spelling officially.

Propagator!

[LisoUseInAIKyrios]

There's unrelated file changes.

Should rebase off dev.

[oSumAtrIX]

The other PRs should be linked here too