Update docs of cancel_{minus,plus}

[unageek]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 1908088941

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 83.666%

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Totals
Change from base Build 1907902528:	0.0%
Covered Lines:	2102
Relevant Lines:	2145

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💛 - Coveralls

[Chris00]

There is not a unique interval that satisfies rhs + z ⊇ self. That's why the norm says the tightest.

[unageek]

Wow… it's so dumb mistake. Thank you so much for pointing it out! I revert the change now, and I'll ask for your review when I make another change to the doc.