`url_to_path` discards fragment anyway (5th element of
urllib_parse.urlsplit)

…xtras

Remove unnecessary else in convert_extras

A few cleanups in req_set.py

Remove download dependency from wheel

As things stand, it'll completely delegate all the metadata generation
to InstallRequirement's methods.

Follow ups will move related code into this module.

Validate NEWS files with rstcheck.

…parsing

Refactoring req.constructors requirement parsing

Because it was a little difficult to follow.
Because the comments weren't helpful unless you've built enough context.

…ring

Add documentation string to pip._internal.network.auth

This is only relevant for our usage of --trusted-host, so it is enough
to initialize it in network.session.

…a#6888)

Rename tests.lib.path.Path.{abspath -> resolve()}

…a#7158)

Revert "Optimize upgrade of already-satisfied pinned requirement"

Delete 1234.trival

Saves >=10ms on irrelevant platforms.

Move some initialization out of __init__