diff-apply-hunk
diff-apply-hunk is an interactive compiled Lisp function in `diff-mode.el
'.
(diff-apply-hunk &optional REVERSE)
Apply the current hunk to the source file and go to the next.
By default, the new source file is patched, but if the variable
`diff-jump-to-old-file' is non-nil, then the old source file is
patched instead (some commands, such as `diff-goto-source' can change
the value of this variable when given an appropriate prefix argument).
With a prefix argument, REVERSE the hunk.