bpo-43400: Remove "easy to use" from mock docs

[eppeters]

https://bugs.python.org/issue43400

From the original issue message:

The unittest.mock library is very useful and very powerful, but it is not "very easy to use." Docs are useful and important, or we wouldn't be here in a documentation issue.

I have watched several of the most experienced Python programmers I know struggle with various aspects of mock, including basic usage. I have sat with frustrated developers who have used mocking utilities in other languages but had little Python experience, and they were surprised by some mock behaviors and just couldn't get things "right" until they were helped by someone with all the tiny little healed-over cuts from lots of mock usage.

Again, mock is great, but maybe if I have these opinions, I should contribute to making mock more intuitive. That's true. For now, though, the documentation contains this little line in the opening paragraphs that is unnecessary and can only make new mock users feel bad about having trouble: "Mock is very easy to use and is designed for use with unittest."

I propose we remove the opinion "Mock is very easy to use" and change this line to "Mock is designed for use with unittest." The rest of the paragraph flows just fine without this:

"Mock is very easy to use and is designed for use with unittest. Mock is based on the ‘action -> assertion’ pattern instead of ‘record -> replay’ used by many mocking frameworks."

https://bugs.python.org/issue43400

[the-knights-who-say-ni]

Hello, and thanks for your contribution!

I'm a bot set up to make sure that the project can legally accept this contribution by verifying everyone involved has signed the PSF contributor agreement (CLA).

CLA Missing

Our records indicate the following people have not signed the CLA:

@eppeters

For legal reasons we need all the people listed to sign the CLA before we can look at your contribution. Please follow the steps outlined in the CPython devguide to rectify this issue.

If you have recently signed the CLA, please wait at least one business day
before our records are updated.

You can check yourself to see if the CLA has been received.

Thanks again for the contribution, we look forward to reviewing it!

[rhettinger]

I suggest combining the two sentences.

s/. Mock/, and/

[eppeters]

Done, though I removed the comma in the substitution since the part after "and" is not an independent clause. Thanks for the review! It's a little change, but it's good to make Python more approachable however we can.

[miss-islington]

Thanks @eppeters for the PR, and @rhettinger for merging it 🌮🎉.. I'm working now to backport this PR to: 3.9.
🐍🍒⛏🤖

[bedevere-bot]

GH-24758 is a backport of this pull request to the 3.9 branch.