Change `itunes` to `music`, as iTunes was renamed to Music in _**macOS** Catalina 10.15_

Co-authored-by: Marc Cornellà <marc.cornella@live.com>

Fixes #8368

* Update http to https in Solarized
* Upgrade http to https for 'Burger In Your Shell'
* Upgrade http to https for tmux.github.io

Piping stdin to emacs alias on MacOS was breaking (--tmpdir is not
supported in BSD flavored mktemp).

Tested in MacOS 10.14 and debian:buster to confirm it still works in
linux.

Closes #2214

$GIT_STATUS_IGNORE_SUBMODULES can be used to specify handling of
submodules. It can be:
not set : ignore dirty submodules (this was default zsh behavior)
"git"   : do not use "--ignore-submodules" and let git choose,
          this obeys setting in .gitmodules
other   : comes into "--ignore-submodules=$GIT_STATUS_IGNORE_SUBMODULES"

Fixes #8337

Never use `[[` for numeric comparisons, for that, we’ll use `((`.

Deleting `.mypy_cache` did not work, because the directories were not
empty.  They contain JSON files instead of compiled byte-code.

This extends the cleanup by also getting rid of `.pytest_cache`
directories.

* Add profiles documentation

* Fix order and reword some things

Co-authored-by: Marc Cornellà <marc.cornella@live.com>

- core.autocrlf=false -> #4069
- fsck.zeroPaddedFilemode -> #4963

Fixes #4069
Fixes #4963

https://github.com/rust-lang/cargo/blob/cdac4a8/src/etc/_cargo

Sync completion with original source.