Fish: Fix prompt for fish v3.4.1

Removed my own copy of prompt_pwd because fish keeps saying "-d: unknown
option". I hadn't changed anything in the function anyway, so it should
just use the built-in one in /usr/share/fish/functions and it should
work as before.

.config/fish/functions/prompt_pwd.fish

@@ -1,26 +0,0 @@
-# Based on the built-in prompt_pwd.
-function prompt_pwd --description "Print the current working directory, shortened to fit the prompt"
-    set -l options h/help
-    argparse -n prompt_pwd --max-args=0 $options -- $argv
-    or return
-
-    if set -q _flag_help
-        __fish_print_help prompt_pwd
-        return 0
-    end
-
-    # This allows overriding fish_prompt_pwd_dir_length from the outside (global or universal) without leaking it
-    set -q fish_prompt_pwd_dir_length
-    or set -l fish_prompt_pwd_dir_length 1
-
-    # Replace $HOME with "~"
-    set -l realhome ~
-    set -l tmp (string replace -r '^'"$realhome"'($|/)' '~$1' $PWD)
-
-    if [ $fish_prompt_pwd_dir_length -eq 0 ]
-        echo $tmp
-    else
-        # Shorten to at most $fish_prompt_pwd_dir_length characters per directory
-        string replace -ar '(\.?[^/]{'"$fish_prompt_pwd_dir_length"'})[^/]*/' '$1/' $tmp
-    end
-end