patch 9.1.0590: Vim9: crash when accessing getregionpos() return value

Problem:  Vim9: crash when accessing getregionpos() return value.
Solution: Correct the return type (zeertzjq).

fixes: #15272
closes: #15273

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 5c8d9d8..6b77d44 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2024 Jul 11
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Jul 16
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4804,6 +4804,8 @@
 <
 		Can also be used as a |method|: >
 			getpos('.')->getregion(getpos("'a"))
+<
+		Return type: list<string>
 
 <
 getregionpos({pos1}, {pos2} [, {opts}])            *getregionpos()*
@@ -4841,7 +4843,7 @@
 		Can also be used as a |method|: >
 			getpos('.')->getregionpos(getpos("'a"))
 <
-		Return type: list<string>
+		Return type: list<list<list<number>>>
 
 
 getregtype([{regname}])					*getregtype()*