runtime(doc): some improvements to getregion() docs (#14122)

- Mention the default selection behavior
- Remove useless sentence
- Correct description about space padding

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 6d1d372..dbad880 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 Feb 28
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Mar 01
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4281,32 +4281,31 @@
 		The optional argument {opts} is a Dict and supports the
 		following items:
 
-			type		Specify the selection type
+			type		Specify the region's selection type
 					(default: "v"):
 			    "v"		for |characterwise| mode
 			    "V"		for |linewise| mode
 			    "<CTRL-V>"	for |blockwise-visual| mode
 
-			exclusive	If |true|, use exclusive selection
-					for the end position 'selection'.
+			exclusive	If |TRUE|, use exclusive selection
+					for the end position
+					(default: follow 'selection')
 
 		You can get the last selection type by |visualmode()|.
 		If Visual mode is active, use |mode()| to get the Visual mode
 		(e.g., in a |:vmap|).
-		This function uses the line and column number from the
-		specified position.
-		It is useful to get text starting and ending in different
-		columns, such as |characterwise-visual| selection.
+		This function is useful to get text starting and ending in
+		different columns, such as a |characterwise-visual| selection.
 
 		Note that:
 		- Order of {pos1} and {pos2} doesn't matter, it will always
 		  return content from the upper left position to the lower
 		  right position.
-		- If 'virtualedit' is enabled and selection is past the end of
-		  line, resulting lines are filled with blanks.
-		- If the selection starts or ends in the middle of a multibyte
-		  character, it is not included but its selected part is
-		  substituted with spaces.
+		- If 'virtualedit' is enabled and the region is past the end
+		  of the lines, resulting lines are padded with spaces.
+		- If the region is blockwise and it starts or ends in the
+		  middle of a multi-cell character, it is not included but
+		  its selected part is substituted with spaces.
 		- If {pos1} or {pos2} is not current in the buffer, an empty
 		  list is returned.