Small meta cleanups (#4893)

* Remove the unneeded pytest options from pyproject.toml

* Clean up setup.py from old readthedocs.org workaround

* Removes unused folder

* Simplify list of excluded files in black's configuration

* Fix returned exit codes in `make.ps1`

* Add Sublime's project files to `.gitignore`

* Update the link to Black in README and contributing guidelines

.gitignore

@@ -15,6 +15,8 @@ Pipfile.lock
 .idea/
 *.iws
 .vscode/
+*.sublime-project
+*.sublime-workspace
 
 ## Plugin-specific files: