The only readily available keybinding for joining channels in slack is for
joining public channels. This commit adds bindings for joining private
channels, (called groups in emacs-slack) as well as a keybinding for
slack-select-rooms which allows joining a channel, group, or DM.
This commit also rebinds the major mode `k` to slack-select-rooms, which puts it
more in line with how the related keybinding in the slack client works.
- Apply `/` and `//` rules (double / is for private functions)
- Add missing `spacemacs/` prefixes
- Move functions used outside of spacemacs-base layer to
core/core-funcs.el
- Remove unused functions
Commit originally intented to only rename linum-update-window-scale-fix
to spacemacs/linum-update-window-scale-fix :-)
