Fix #5953, pcre2el should be a post-init in spacemacs-editing.

[punassuming]

This gets rid of the warning on load. spacemacs-base will always be loaded, regardless of the distribution used. Call in spacemacs-editing will add keybindings.

[TheBB]

This won't do it. Now nobody without ivy will get pcre2el functionality. There should be an init function in a very basic layer and then both ivy and editing should have post-init functions.

[punassuming]

Yes you are right, I will fix this.

[punassuming]

@StreakyCobra, @TheBB, I updated this PR to put the primary init in spacemacs-base. Since base will always be loaded, we shouldn't have any issues with ivy anymore.

[punassuming]

@syl20bnr , I noticed your comments in the source about this. We need to load pcre2el in the base as it is used outside of just spacemacs-editing. For example, ivy also needs it with our custom counsel-search function which uses rxt-quote-pcre, also it is used in helm layer.

[syl20bnr]

Thank you ! 👍
I changes the invasive SPC R prefix for pcre2el to SPC x r, it allowed me to move safely the whole configuration (key bindings) of pcre2el to spacemacs-base.
Cherry-picked into develop branch, you can safely delete your branch.