patch 9.1.1605: cannot specify scope for chdir()

Problem:  Cannot specify scope for chdir()
Solution: Add optional scope argument (kuuote)

closes: #17888

Signed-off-by: kuuote <znmxodq1@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -1783,16 +1783,23 @@ charidx({string}, {idx} [, {countcc} [, {utf16}]])
 		Return type: |Number|
 
 
-chdir({dir})						*chdir()*
-		Change the current working directory to {dir}.  The scope of
-		the directory change depends on the directory of the current
-		window:
-			- If the current window has a window-local directory
-			  (|:lcd|), then changes the window local directory.
-			- Otherwise, if the current tabpage has a local
-			  directory (|:tcd|) then changes the tabpage local
-			  directory.
-			- Otherwise, changes the global directory.
+chdir({dir} [, {scope}])				*chdir()*
+		Changes the current working directory to {dir}.  The scope of
+		the change is determined as follows:
+		If {scope} is not present, the current working directory is
+		changed to the scope of the current directory:
+		    - If the window local directory (|:lcd|) is set, it
+		      changes the current working directory for that scope.
+		    - Otherwise, if the tab page local directory (|:tcd|) is
+		      set, it changes the current directory for that scope.
+		    - Otherwise, changes the global directory for that scope.
+
+		If {scope} is present, changes the current working directory
+		for the specified scope:
+		    "window"	Changes the window local directory.  |:lcd|
+		    "tabpage"	Changes the tab page local directory.  |:tcd|
+		    "global"	Changes the global directory.  |:cd|
+
 		{dir} must be a String.
 		If successful, returns the previous working directory.  Pass
 		this to another chdir() to restore the directory.

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2025 Jul 25
+*version9.txt*  For Vim version 9.1.  Last change: 2025 Aug 08
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41722,6 +41722,7 @@ Functions: ~
   not finished
 - Add the optional {opts} |Dict| argument to |getchar()| to control: cursor
   behaviour, return type and whether or not to simplify the returned key
+- |chdir()| allows to optionally specify a scope argument
 
 Others: ~
 - the regex engines match correctly case-insensitive multi-byte characters