limit save history size

[practicalli-johnny]

Spacemacs can degrade in performance when save history files grow.

Set limits on the size of key history files in the `dotspacemacs/user-config section of the Spacemacs user config

(setq history-length 100)
(put 'minibuffer-history 'history-length 50)
(put 'evil-ex-history 'history-length 50)
(put 'kill-ring 'history-length 25)

It may be valuable to clear the history files in the .cache directory of the Spacemacs configuration, e.g .config/Emacs/.cache or .emacs.d/.cache

Spacemacs issue discussion
syl20bnr/spacemacs#9409 (comment)

Stack exchange question
https://emacs.stackexchange.com/questions/12086/high-cpu-memory-usage-and-abnormally-large-savehist-file