rebase.c: state preserve-merges has been removed

Since feebd2d (rebase: hide --preserve-merges option, 2019-10-18)
this option is now removed as stated in the subsequent release notes.

Fix and reflow the option tip.

Signed-off-by: Philip Oakley <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: PhilipOakley

builtin/rebase.c

@@ -1110,8 +1110,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 			parse_opt_interactive),
 		OPT_SET_INT_F('p', "preserve-merges", &preserve_merges_selected,
-			      N_("(DEPRECATED) try to recreate merges instead of "
-				 "ignoring them"),
+			      N_("(REMOVED) was: try to recreate merges "
+				 "instead of ignoring them"),
 			      1, PARSE_OPT_HIDDEN),
 		OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
 		OPT_CALLBACK_F(0, "empty", &options, "{drop,keep,ask}",