Don't trim when onType-reformatting the document

[pbwolf]

What has changed?

One must be able to add a newline to the end of a document, but doing so triggers format-on-type, which therefore should not briskly remove the new newline.

Format-as-you-type reformats the entire document under some circumstances. In that case it did not check whether the reason for reformatting was format-as-you-type. The change reduces trimming in that case.

Fixes #2778

My Calva PR Checklist

I have:

• Read How to Contribute.
• Directed this pull request at the dev branch. (Or have specific reasons to target some other branch.)
• Made sure I have changed the PR base branch, so that it is not published. (Sorry for the nagging.)
• Made sure there is an issue registered with a clear problem statement that this PR addresses, (created the issue if it was not present).
  • Updated the [Unreleased] entry in CHANGELOG.md, linking the issue(s) that the PR is addressing.
• Figured if anything about the fix warrants tests on Mac/Linux/Windows/Remote/Whatever, and either tested it there if so, or mentioned it in the PR.
• Added to or updated docs in this branch, if appropriate
• Tests
  • Tested the particular change
  • Figured if the change might have some side effects and tested those as well.
• Formatted all JavaScript and TypeScript code that was changed. (use the prettier extension or run npm run prettier-format)
• Confirmed that there are no linter warnings or errors (use the eslint extension, run npm run eslint before creating your PR, or run npm run eslint-watch to eslint as you go).

Ping @PEZ, @bpringe, @corasaurus-hex, @Cyrik

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[PEZ]

Thanks!