patch 8.2.3979: Vim9: the feature is not mentioned in the right places

Problem:    Vim9: the feature is not mentioned in the right places.
Solution:   Add +vim9script to the help and :version output.

runtime/doc/builtin.txt

@@ -10069,6 +10069,7 @@ vertsplit		Compiled with vertically split windows |:vsplit|.
 			(always true)
 vim_starting		True while initial source'ing takes place. |startup|
 			*vim_starting*
+vim9script		Compiled with |Vim9| script support
 viminfo			Compiled with viminfo support.
 vimscript-1		Compiled Vim script version 1 support
 vimscript-2		Compiled Vim script version 2 support

runtime/doc/various.txt

@@ -476,9 +476,10 @@ N  *+toolbar*		|gui-toolbar|
 T  *+user_commands*	User-defined commands. |user-commands|
 			Always enabled since 8.1.1210.
 B  *+vartabs*		Variable-width tabstops. |'vartabstop'|
-N  *+viminfo*		|'viminfo'|
 T  *+vertsplit*		Vertically split windows |:vsplit|; Always enabled
 			since 8.0.1118.
+T  *+vim9script*	|Vim9| script
+N  *+viminfo*		|'viminfo'|
 T  *+virtualedit*	|'virtualedit'| Always enabled since 8.1.826.
 T  *+visual*		Visual mode |Visual-mode| Always enabled since 7.4.200.
 T  *+visualextra*	extra Visual mode commands |blockwise-operators|

src/version.c

@@ -661,14 +661,15 @@ static char *(features[]) =
 	"-vartabs",
 #endif
 	"+vertsplit",
-	"+virtualedit",
-	"+visual",
-	"+visualextra",
+	"+vim9script",
 #ifdef FEAT_VIMINFO
 	"+viminfo",
 #else
 	"-viminfo",
 #endif
+	"+virtualedit",
+	"+visual",
+	"+visualextra",
 	"+vreplace",
 #ifdef MSWIN
 # ifdef FEAT_VTP
@@ -749,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3979,
 /**/
     3978,
 /**/