Restricting to current matches in Icicles, Ido and Ivy

An effect equivalent to matching multiple components in any order can be achieved in completion frameworks that provide a way to restrict further matching to the current list of candidates. If you use the keybinding for restriction instead of ‘SPC’ to separate your components, you get out of order matching!

• Icicles calls this progressive completion and uses the ‘icicle-apropos-complete-and-narrow’ command, bound to ‘S-SPC’, to do it.
• Ido has ‘ido-restrict-to-matches’ and binds it to ‘C-SPC’.
• Ivy has ‘ivy-restrict-to-matches’, bound to ‘S-SPC’, so you can get the effect of out of order matching without using ‘ivy--regex-ignore-order’.