Expand documentation of `git` dependency subkeys

I need to pin a dependency to a specific git commit hash. After reading
these docs, it was not clear to me that I could do so with the `rev`
key, because "something else" is vague. I wound up digging into the
source code and learned what I needed there.

This change expands the documentation for `git` dependencies to explain
the sub-keys in more detail and give examples of how to use each.

* Removing setecho(False) for all shells

* Only setecho(False) for zsh

* fix (setup_reader): in `setup.py` the `setup()` method can also be called by `setuptools.setup()`

* fix (setup_reader): make black happy

* fix (setup_reader): skip test for python <3.4

Fixed typo

Without this fix the helptext shows as:
```
  version                Shows the version of the project or bumps it when a validbump rule is provided.
```

Fix syntax errors in typehints

Fix simple typo: specificed -> specified

Closes #1753

Fixed default cache-dir path in docs.

Fixes #1735

fix: change `self:update` to `self update` in docs and add hint about different syntax in earlier version (#1712)

* fix (locker): add `develop = false` in `poetry.lock` if set in `pyproject.toml`
fix (locker): read `develop` value from `poetry.lock` so it is respect when exporting to `requirements.txt`

* fix (test_installer): adopt expected result

* change (test_installer): move develop key from source to package in lock file

* fix (test_installer): make black happy

* do not write empty or any markers

* Update poetry/version/markers.py

Co-Authored-By: Sébastien Eustace <sebastien.eustace@gmail.com>

* Update test_markers.py

Fix typo + reformat help in LockCommand

added install instruction for powershell users