Clojurians Log v2

I've create https://github.com/syl20bnr/spacemacs/pull/15948, a handy tool for showing keybindings and commands as you type. Keycast has already been added to the command-log layer and includes the keycast-tab-bar-mode, keycast-header-line-mode and keycast-mode-line-mode commands (although the modeline insertion is classed as experimental - it seems to replace everything on the modeline with itself, rather than be incorporated with other info). If you have ideas of how to insert keycast in the mode line along with other information then it would be most welcome. I find keycast useful for • learning commands (or figuring out what I did when something unexpected happened) • demos and screencasts so people can easily follow the key bindings and commands used (hopefully there will be more Practicalli screencasts this year) The tab bar to be the best placement for the keycast output, which appears in the top-right of the frame