🎨 Shorten the long line

Use str.format to format in the long line.

pip/commands/completion.py

@@ -33,12 +33,12 @@ COMPLETION_SCRIPTS = {
     'fish': """
         function __fish_complete_pip
             set -lx COMP_WORDS (commandline -o) ""
-            set -lx COMP_CWORD (math (contains -i -- (commandline -t) $COMP_WORDS)-1)
+            set -lx COMP_CWORD {cword}
             set -lx PIP_AUTO_COMPLETE 1
             string split \\  -- (eval $COMP_WORDS[1])
         end
         complete -fa "(__fish_complete_pip)" -c pip
-    """
+    """.format(cword="(math (contains -i -- (commandline -t) $COMP_WORDS)-1)")
 }