Standardize REPL commands & improve SPC o r

- SPC o r now prompts for a REPL to open when none was found for the
  current buffer.
- REPL handlers must now follow the naming convention "*/open*-repl".
  e.g. +python/open-ipython-repl, +emacs-lisp/open-repl, etc.
- +eval/open-repl has been split in two:
  - +eval/open-repl-other-window
  - +eval/open-repl-same-window

modules/lang/python/config.el

@@ -26,7 +26,7 @@ called.")
   :config
   (set-env! "PYTHONPATH" "PYENV_ROOT" "ANACONDA_HOME")
   (set-electric! 'python-mode :chars '(?:))
-  (set-repl-handler! 'python-mode #'+python/repl)
+  (set-repl-handler! 'python-mode #'+python/open-repl)
 
   (set-pretty-symbols! 'python-mode
     ;; Functional