patch 9.1.0394: Cannot get a list of positions describing a region

Problem:  Cannot get a list of positions describing a region
          (Justin M. Keyes, after v9.1.0120)
Solution: Add the getregionpos() function
          (Shougo Matsushita)

fixes: #14609
closes: #14617

Co-authored-by: Justin M. Keyes <justinkz@gmail.com>
Signed-off-by: Shougo Matsushita <Shougo.Matsu@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index f62cc83..b37170c 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 May 05
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 May 07
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -265,6 +265,8 @@
 getreginfo([{regname}])		Dict	information about a register
 getregion({pos1}, {pos2} [, {opts}])
 				List	get the text from {pos1} to {pos2}
+getregionpos({pos1}, {pos2} [, {opts}])
+				List	get a list of positions for a region
 getregtype([{regname}])		String	type of a register
 getscriptinfo([{opts}])		List	list of sourced scripts
 gettabinfo([{expr}])		List	list of tab pages
@@ -4327,6 +4329,26 @@
 		Can also be used as a |method|: >
 			getpos('.')->getregion(getpos("'a"))
 <
+getregionpos({pos1}, {pos2} [, {opts}])            *getregionpos()*
+		Same as |getregion()|, but returns a list of positions
+		describing the buffer text segments bound by {pos1} and
+		{pos2}.
+		The segments are a pair of positions for every line: >
+			[[{start_pos}, {end_pos}], ...]
+<
+		The position is a |List| with four numbers:
+		    [bufnum, lnum, col, off]
+		"bufnum" is the buffer number.
+		"lnum" and "col" are the position in the buffer.  The first
+		column is 1.
+		The "off" number is zero, unless 'virtualedit' is used.  Then
+		it is the offset in screen columns from the start of the
+		character.  E.g., a position within a <Tab> or after the last
+		character.
+
+		Can also be used as a |method|: >
+			getpos('.')->getregionpos(getpos("'a"))
+<
 getregtype([{regname}])					*getregtype()*
 		The result is a String, which is type of register {regname}.
 		The value will be one of: