clarify language options

[Die4Ever]

Requirements

• [X] This is a feature request and not a bug report. Otherwise, please create a new bug report instead.
• [X] Please check to see if this request (or a similar one) already exists.
• [X] It's a single feature. Please don't request multiple features in one issue.

Describe the feature you'd like

on the user settings profile: instead of "undetermined" it should say something like "Show All"

when making a post: maybe it could say "any"? or maybe "undetermined" is fine here

from discussion here https://lemmy.ml/comment/7241277