Don't re-run work_directory function

- Re-reunning work_directory every time we redraw the prompt isn't
  necessary, since the function is here to generate the zsh supported
  syntax for the prompt that will get expanded into a work directory
  automatically.
- The function is only here to determine whether we're in TTY and use
  ASCII compatible symbols if we are, however it is enough to only check
  this once initially, since we can't leave TTY in favor of a graphical
  instance without reloading the rc file and neither can we leave.
- However, this function also checks for `USE_SHORTENED_WORKDIR`
  variable and decides which prompt to show based on it. This means that
  it someone was setting this variable in their profile file it would
  now no longer be respected, however this was never the intention of
  that variable, if a change is desired, the variable should simply be
  edited in the prompt file directly.
- Removing continual calls to this function each time prompt is redrawn
  is worth the very minor inconvenience of no longer supporting
  shortened workdirs from externally set variable due to the speed
  benefit it gives us, though not that noticeable, it is pretty
  significant. Not to mention that this wasn't intended/recommended
  usage anyway.

home/.config/shell/prompt

@@ -66,7 +66,7 @@ foreign_prompt() {
 	fi
 }
 
-# Prints appropriate working directory
+#nd Prints appropriate working directory
 working_directory() {
 	# By default up to 5 directories will be tolerated before shortening
 	# After we surpass that, first directory (or ~) will be printed together with last 3
@@ -148,7 +148,7 @@ add-zsh-hook precmd exec_time_precmd_hook
 # Primary Prompt
 [ "$EUID" -eq 0 ] && PS1="$RED%n$RESET" || PS1="$GREEN%n$RESET" # user
 PS1+="$(foreign_prompt)"
-PS1+="\$(working_directory)"
+PS1+="$(working_directory)"
 PS1+="\$(git_prompt)"
 PS1+="\$(display_cmd_time)"
 PS1+=" $PURPLE%(!.#.$)$RESET " # Final symbol (# or $)