Tone down diff-refine-removed and diff-refine-added as well

* lisp/vc/diff-mode.el (diff-refine-removed, diff-refine-added):
Change backgrounds in light backgrounds themes (bug#33567).

lisp/vc/diff-mode.el

@@ -2026,7 +2026,7 @@ For use in `add-log-current-defun-function'."
   '((default
      :inherit diff-refine-changed)
     (((class color) (min-colors 88) (background light))
-     :background "#ffbbbb")
+     :background "#ffcccc")
     (((class color) (min-colors 88) (background dark))
      :background "#aa2222"))
   "Face used for removed characters shown by `diff-refine-hunk'."
@@ -2036,7 +2036,7 @@ For use in `add-log-current-defun-function'."
   '((default
      :inherit diff-refine-changed)
     (((class color) (min-colors 88) (background light))
-     :background "#aaffaa")
+     :background "#bbffbb")
     (((class color) (min-colors 88) (background dark))
      :background "#22aa22"))
   "Face used for added characters shown by `diff-refine-hunk'."