Docs: shutil: Hide module name from local (anchor) links

[aureliojargas]

Inside all the methods descriptions, local links to other shutil methods do not show the module name.

For example, it's:

• copy2() uses copystat() to copy the file metadata.

not:

• shutil.copy2() uses shutil.copystat() to copy the file metadata.

This commit fixes the very few outliers that were not following that pattern.

[the-knights-who-say-ni]

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[aureliojargas]

I've signed the CLA.

No issue number since this is a very simple documentation fix.

No news entry is necessary.

[BoboTiG]

Thanks @aureliojargas! Do you mind updating you branch to resolve the conflict?

[aureliojargas]

Done. Tests are green again.

[miss-islington]

Thanks @aureliojargas for the PR, and @csabella for merging it 🌮🎉.. I'm working now to backport this PR to: 3.7.
🐍🍒⛏🤖

[miss-islington]

Sorry, @aureliojargas and @csabella, I could not cleanly backport this to 3.7 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker f6e17ddffd3ba52a08e977bd9c6c0d6f2fffa905 3.7

[csabella]

@aureliojargas Thank you for the suggestion and the pull request. Your change has now been merged. 🎉 🎉