Fix typos, American English, sync with interface
Summary: Fix typos, consistent view naming, colour -> color, sync with interface
Test Plan: none
Reviewers: Krita, Krita: Manual, woltherav
Reviewed By: Krita, Krita: Manual, woltherav
Subscribers: woltherav
Tags: Krita: Manual
Differential Revision: https://phabricator.kde.org/D20146