English Language Update

- Ran en_US through a spellchecker at multiple times, correcting for the English language where appropriate, was briefly tested in the mod, but gave up on testing due to not actually playing the mod much and no easy way to lang test exists. If there's a way to check all the in game wiki pages at once or a fully unlocked save somewhere I could use, I'll check and update the patch myself.
- Copied en_US to en_GB, brought it up to date via git and manual fudgery, corrected spelling to British counterparts where appropriate and needed (as per British spell check suggestions). Suggest changing "default" language that Azanor edits to it from now on based on initial spelling commits. Maybe en_CA depending on dialect.
- Also accomplish initial goal of actually fixing Issues #1134 and #1136 while in there as it took a whole ... three minutes to do so on both files.
Even though I know this is right, the change from British English to American English somewhat hurts me :|
I am not sure whether it should be applied, remember that thaumaturgy appeared in Britain; this could be used as an excuse to keep the file British English (and then fix https://github.com/Azanor/thaumcraft/pull/1210/files#r18746301)