The default `disabled: true` is actually only available within the module (when the config struct is used and not the user toml) but not all (the hg_branch) modules checked it there again.
Document this in all places and add the check (+ test) to the hg_branch module.
* initial commit of support for shlvl
* documentation for shlvl
* use a symbol instead
* test coverage for shlvl
* actually disable when the config says to
* fix docs
* tweak defaults some
* refactor from pr comments
* redisable
* return early to avoid indenting
* make default suffix empty space
* fixing tests after suffix change
* updating docs for format
* making shlvl compatible with formatting
* adding variables table for shlvl
* removing extra line
* doc clarity
