patch 9.1.1544: :retab cannot be limited to indentation only

Problem:  :retab cannot be limited to indentation only
Solution: add the optional -indentonly parameter
          (Hirohito Higashi)

closes: #17730

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2025 Jul 11
+*builtin.txt*	For Vim version 9.1.  Last change: 2025 Jul 14
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4333,6 +4333,7 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		messages	|:messages| suboptions
 		option		options
 		packadd		optional package |pack-add| names
+		retab		|:retab| suboptions
 		runtime		|:runtime| completion
 		scriptnames	sourced script names |:scriptnames|
 		shellcmd	Shell command

runtime/doc/change.txt

@@ -1,4 +1,4 @@
-*change.txt*    For Vim version 9.1.  Last change: 2025 Jun 26
+*change.txt*    For Vim version 9.1.  Last change: 2025 Jul 14
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -991,22 +991,26 @@ This replaces each 'E' character with a euro sign.  Read more in |<Char->|.
 
 4.4 Changing tabs					*change-tabs*
 							*:ret* *:retab* *:retab!*
-:[range]ret[ab][!] [new_tabstop]
+:[range]ret[ab][!] [-indentonly] [{new-tabstop}]
 			Replace all sequences of white-space containing a
-			<Tab> with new strings of white-space using the new
-			tabstop value given.  If you do not specify a new
-			tabstop size or it is zero, Vim uses the current value
-			of 'tabstop'.
+			<Tab> with new strings of white-space using
+			{new-tabstop}.  If you do not specify {new-tabstop} or
+			it is zero, Vim uses the current value of 'tabstop'.
 			The current value of 'tabstop' is always used to
 			compute the width of existing tabs.
 			With !, Vim also replaces strings of only normal
 			spaces with tabs where appropriate.
 			With 'expandtab' on, Vim replaces all tabs with the
 			appropriate number of spaces.
-			This command sets 'tabstop' to the new value given,
-			and if performed on the whole file, which is default,
-			should not make any visible change.
-			Careful: This command modifies any <Tab> characters
+			This command sets 'tabstop' to {new-tabstop} and if
+			performed on the whole file, which is default, should
+			not make any visible change.
+
+			When [-indentonly] is specified, only the leading
+			white-space will be targeted. Any other consecutive
+			white-space will not be changed.
+
+			Warning: This command modifies any <Tab> characters
 			inside of strings in a C program.  Use "\t" to avoid
 			this (that's a good habit anyway).
 			`:retab!` may also change a sequence of spaces by

runtime/doc/map.txt

@@ -1,4 +1,4 @@
-*map.txt*       For Vim version 9.1.  Last change: 2024 Oct 08
+*map.txt*       For Vim version 9.1.  Last change: 2025 Jul 14
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -1654,6 +1654,7 @@ completion can be enabled:
 	-complete=messages	|:messages| suboptions
 	-complete=option	options
 	-complete=packadd	optional package |pack-add| names
+	-complete=retab		|:retab| suboptions
 	-complete=runtime	file and directory names in |'runtimepath'|
 	-complete=scriptnames	sourced script names
 	-complete=shellcmd	Shell command

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2025 Jul 10
+*version9.txt*  For Vim version 9.1.  Last change: 2025 Jul 14
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41692,6 +41692,8 @@ Ex commands: ~
   documented and skips help buffers (if not run from a help buffer, else
   moves to the next/previous help buffer).
 - |:keeppatterns| preserves the last substitute pattern when used with |:s|
+- |:retab| accepts the new optional parameter -indentonly to only change
+  whitespace in indented lines.
 
 Functions: ~
 - provide information about function arguments using the get(func, "arity")

runtime/syntax/vim.vim

@@ -2,7 +2,7 @@
 " Language:	   Vim script
 " Maintainer:	   Hirohito Higashi <h.east.727 ATMARK gmail.com>
 "	   Doug Kearns <dougkearns@gmail.com>
-" Last Change:	   2025 Jul 11
+" Last Change:	   2025 Jul 14
 " Former Maintainer: Charles E. Campbell
 
 " DO NOT CHANGE DIRECTLY.
@@ -842,7 +842,7 @@ syn case ignore
 syn keyword	vimUserCmdAttrKey   contained	a[ddr] ban[g] bar bu[ffer] com[plete] cou[nt] k[eepscript] n[args] ra[nge] re[gister]
 
 " GEN_SYN_VIM: vimUserCmdAttrComplete, START_STR='syn keyword vimUserCmdAttrComplete contained', END_STR=''
-syn keyword vimUserCmdAttrComplete contained arglist augroup behave breakpoint buffer color command compiler cscope diff_buffer dir dir_in_path environment event expression file file_in_path filetype filetypecmd function help highlight history keymap locale mapclear mapping menu messages option packadd runtime scriptnames shellcmd shellcmdline sign syntax syntime tag tag_listfiles user var
+syn keyword vimUserCmdAttrComplete contained arglist augroup behave breakpoint buffer color command compiler cscope diff_buffer dir dir_in_path environment event expression file file_in_path filetype filetypecmd function help highlight history keymap locale mapclear mapping menu messages option packadd retab runtime scriptnames shellcmd shellcmdline sign syntax syntime tag tag_listfiles user var
 syn keyword vimUserCmdAttrComplete contained arglist augroup behave breakpoint buffer color command compiler cscope diff_buffer dir dir_in_path environment event expression file file_in_path filetype function help highlight history keymap locale mapclear mapping menu messages option packadd runtime scriptnames shellcmd shellcmdline sign syntax syntime tag tag_listfiles user var
 syn keyword	vimUserCmdAttrComplete	contained	custom customlist nextgroup=vimUserCmdAttrCompleteFunc,vimUserCmdError
 syn match	vimUserCmdAttrCompleteFunc	contained	",\%([bwglstav]:\|<[sS][iI][dD]>\)\=\h\w*\%([.#]\h\w*\)*"hs=s+1 nextgroup=vimUserCmdError contains=vimVarScope,vimFunctionSID