Standardize to W3C naming for color.

[dannon]

I thought about this right after merging #16612. We have previously always used color instead of colour in the application, and I think we should stick with it. The sans-u spellings are the expected spellings in html/css and computing in general, and I can see this being problematic down the road when these things are serialized out, potentially hand-edited, etc. We need to be consistent here, at least in the codebase and potentially serialized artifacts. I'm not particularly worried about language choice in news briefs, blog posts, etc., just in the technical bits.

This will probably flag an error in tests as it was a pretty quick find and replace, but I wanted to open it ASAP for testing so we can do this without needing a second migration to rename the column.

How to test the changes?

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• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[jdavcs]

Can you, please, move the migration into a separate commit?

[dannon]

@jdavcs It's not a new migration -- it's tweaking one that was just added in the parent commits merged hours ago. I can make a separate migration if we need to, but it felt like overkill for something nobody should have applied yet.

[jdavcs]

Oh yeah, I see now. It will break things for anyone using dev though (all devs - staff and anyone else contributing). I think it's OK to make a migration: it's a perfectly legit reason for a migration; besides, it could have happened across releases, in which case we'd have to anyway.