Fix the URL to fishshell.com (GH-20251)

(cherry picked from commit da7d1f0408)

Co-authored-by: Jonathan Goble <jcgoble3@gmail.com>

Lib/venv/scripts/posix/activate.fish

@@ -1,5 +1,5 @@
 # This file must be used with "source <venv>/bin/activate.fish" *from fish*
-# (http://fishshell.org); you cannot run it directly.
+# (https://fishshell.com/); you cannot run it directly.
 
 function deactivate  -d "Exit virtual environment and return to normal shell environment"
     # reset old environment variables