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

`git rev-parse --is-inside-work-tree` does not have a different exit
code when not within a work tree; the difference is in the output,
either "true" when in a work tree, or "false" when not.

The if was modified similarly to the check for the hide-status config,
which also parses command output rather than exit code.

Co-authored-by: Kyle Laker <klaker@easydynamics.com>

Changing 'your' to 'you'

Fixes #8730

DISABLE_UNTRACKED_FILES_DIRTY, DISABLE_AUTO_TITLE, GIT_STATUS_IGNORE_SUBMODULES are not set
Handle these variables not being set with conditional access.

If the user has set -u option to report attempts to use undeclared / unassigned variable, accessing the variables needs to be conditional.

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

* mvn: add mvnfmt alias

* mvn: update README.md

Co-authored-by: Magnus Boman <Kattus@users.noreply.github.com>

skip the update check at initialization if DISABLE_AUTO_UPDATE is set to true

Co-authored-by: Capybara <git.capybara@gmail.com>
Co-authored-by: drootang <drootang@users.noreply.github.com>
Co-authored-by: Augusto Souza <augustorsouza@gmail.com>
Co-authored-by: PatrBal <44707588+PatrBal@users.noreply.github.com>

Fixes #5244

Fixes #8998

Closes #7157

oh-my-zsh Changes the HISTSIZE and SAVEHIST values to fixed sizes,
however if a bigger value is set in ~/.zshrc, it will override it,
potentially causing the user history to be deleted.

So, only set these values if no other is set and if it is lower than the
default ones.

Closes #8981