patch 9.0.0729: the rightleft and arabic features are disabled

Problem:    The rightleft and arabic features are disabled.
Solution:   Re-enable the features, some users want to use the functionality.

runtime/doc/rileft.txt

@@ -35,6 +35,11 @@ encoded for every character (or group of characters) are not supported either
 as this kind of support is out of the scope of a simple addition to an
 existing editor (and it's not sanctioned by Unicode either).
 
+As many people working on the code do not use the right-to-left mode, this
+feature may not work in some situations.  If you can describe what is wrong
+and how it would work when fixed, please create an issue on github, see
+|bug-reports|.
+
 
 Highlights
 ----------

src/feature.h

@@ -186,7 +186,7 @@
 #endif
 
 /*
- * +linebreak		'showbreak', 'breakat'  and 'linebreak' options.
+ * +linebreak		'showbreak', 'breakat' and 'linebreak' options.
  *			Also 'numberwidth'.
  */
 #ifdef FEAT_NORMAL
@@ -216,6 +216,8 @@
 
 /*
  * +rightleft		Right-to-left editing/typing support.
+ *			Note that this isn't perfect, but enough users say they
+ *			use it to keep supporting it.
  */
 #if defined(FEAT_HUGE) && !defined(DISABLE_RIGHTLEFT)
 # define FEAT_RIGHTLEFT
@@ -234,18 +236,6 @@
 # endif
 #endif
 
-// It is unclear if there are any users of the +rightleft and +arabic fetures.
-// The lack of feedback and bug reports suggests that they are not actively
-// being used.
-// FOR NOW: disable the features here.  If nobody complains the code can be
-// removed.
-#ifdef FEAT_RIGHTLEFT
-# undef FEAT_RIGHTLEFT
-#endif
-#ifdef FEAT_ARABIC
-# undef FEAT_ARABIC
-#endif
-
 /*
  * +emacs_tags		When FEAT_EMACS_TAGS defined: Include support for
  *			emacs style TAGS file.

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    729,
 /**/
     728,
 /**/