runtime(doc): add help tag multiple-constructors. (#13772)

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/vim9class.txt b/runtime/doc/vim9class.txt
index b71e95f..a7ba2cd 100644
--- a/runtime/doc/vim9class.txt
+++ b/runtime/doc/vim9class.txt
@@ -1,4 +1,4 @@
-*vim9class.txt*	For Vim version 9.0.  Last change: 2023 Dec 24
+*vim9class.txt*	For Vim version 9.0.  Last change: 2023 Dec 25
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -212,6 +212,8 @@
 <
 Simplifying the new() method ~
 						*new()* *constructor*
+See also |default-constructor| and |multiple-constructors|.
+
 Many constructors take values for the object variables.  Thus you very often
 see this pattern: >
 
@@ -801,7 +803,7 @@
 
 
 Multiple constructors ~
-
+						*multiple-constructors*
 Normally a class has just one new() constructor.  In case you find that the
 constructor is often called with the same arguments you may want to simplify
 your code by putting those arguments into a second constructor method.  For