persist: theme persist--directory-location

[cvdub]

• persist.el is a third party package providing variables which persist across sessions.
• persist--directory-location is the location of persist directory where the variables are stored.

[tarsius]

After merging some additions I usually let it sit for a few days but when I finally tag a new release then I can be almost be certain a new pull-request is opened within a few hours. :grin:

[tarsius]

Thanks!