refactor: use the term unmount instead of dismount (#1478) * refactor: use UNMOUNT instead of DISMOUNT in code This change updates the term DISMOUNT in constants to UNMOUNT. Other occurrences (e.g. variable names) are left alone for now. * refactor(ui): use unmount instead of dismount This change updates the GUI text and replaces dismount with unmount. * docs: update term dismount -> unmount * refactor(cmdline): add unmount This change adds an argument 'unmount' for command line usage, while trying to deprecate the old disnount argument. The current dismount argument/flag will still work to not introduce a breaking change. * docs: mention that /dismount is deprecated This change fixes the shorthand version of the argument /unmount It also adds back the info for /dismount and that it is deprecated.