Remove needless whitespace when joining two lines in Chinese

fixup-join-lines-for-chinese.el

(defun et/fixup-whitespace ()
  "Fixup white space between objects around point.
Leave one space or none, according to the context."
  (interactive "*")
  (save-excursion
    (delete-horizontal-space)
    (if (or (looking-at "^\\|\\s)")
            (save-excursion (forward-char -1)
                            ;; we adapted the regexp here:
                            (looking-at "\\cc\\|$\\|\\s(\\|\\s'")))
        nil
      (insert ?\s))))

(defun et/delete-indentation (old-func &rest args)
  (cl-letf (((symbol-function 'fixup-whitespace) #'et/fixup-whitespace))
    (apply old-func args)))

(advice-add #'delete-indentation :around #'et/delete-indentation)