tweaks: remove an old fix that was made superfluous by a recent fix

Commit 43d94692 fixed a miscoloring bug [1] by doing proper backtracking
for multiline regexes.  But this change also solves an older miscoloring
issue [2] without needing to recalculate all the multiline data.  So...
just drop the old fix.  (This isn't perfect: it's probably possible to
cook up a replacement scheme where things get miscolored, but... until
then, this is good enough.)

  [1] https://savannah.gnu.org/bugs/?59948
  [2] https://savannah.gnu.org/bugs/?58481

Also, there is no need to set 'refresh_needed' in do_replace_loop(),
because each replacement prompt will call edit_refresh() anyway, and
the functions that call do_replace_loop() will set it afterward.

src/search.c

@@ -668,13 +668,6 @@ ssize_t do_replace_loop(const char *needle, bool whole_word_only,
 #ifndef NANO_TINY
 			if (ISSET(SOFTWRAP))
 				openfile->current->extrarows = extra_chunks_in(openfile->current);
-#endif
-#ifdef ENABLE_COLOR
-			/* Check whether the replacement requires a change in the coloring. */
-			check_the_multis(openfile->current);
-
-			if (refresh_needed && !replaceall)
-				precalc_multicolorinfo();
 #endif
 			set_modified();
 			as_an_at = TRUE;
@@ -685,11 +678,6 @@ ssize_t do_replace_loop(const char *needle, bool whole_word_only,
 	if (numreplaced == -1)
 		not_found_msg(needle);
 
-#ifdef ENABLE_COLOR
-	if (refresh_needed)
-		precalc_multicolorinfo();
-#endif
-
 #ifndef NANO_TINY
 	openfile->mark = was_mark;
 #endif