vim-patch:9.1.0741: No way to get prompt for input()/confirm()

Problem:  No way to get prompt for input()/confirm()
Solution: add getcmdprompt() function (Shougo Matsushita)
          (Shougo Matsushita)

closes: vim/vim#15667

6908428560

Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>

runtime/doc/builtin.txt

@@ -2361,18 +2361,18 @@ getcmdcompltype()                                            *getcmdcompltype()*
 		Only works when the command line is being edited, thus
 		requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
 		See |:command-completion| for the return string.
-		Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
-		|setcmdline()|.
+		Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+		|getcmdprompt()| and |setcmdline()|.
 		Returns an empty string when completion is not defined.
 
 getcmdline()                                                      *getcmdline()*
-		Return the current command-line.  Only works when the command
-		line is being edited, thus requires use of |c_CTRL-\_e| or
-		|c_CTRL-R_=|.
+		Return the current command-line input.  Only works when the
+		command line is being edited, thus requires use of
+		|c_CTRL-\_e| or |c_CTRL-R_=|.
 		Example: >vim
 			cmap <F7> <C-\>eescape(getcmdline(), ' \')<CR>
-<		Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()| and
-		|setcmdline()|.
+<		Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()|,
+		|getcmdprompt()| and |setcmdline()|.
 		Returns an empty string when entering a password or using
 		|inputsecret()|.
 
@@ -2382,8 +2382,16 @@ getcmdpos()                                                        *getcmdpos()*
 		Only works when editing the command line, thus requires use of
 		|c_CTRL-\_e| or |c_CTRL-R_=| or an expression mapping.
 		Returns 0 otherwise.
-		Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
-		|setcmdline()|.
+		Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+		|getcmdprompt()| and |setcmdline()|.
+
+getcmdprompt()                                                  *getcmdprompt()*
+		Return the current command-line prompt when using functions
+		like |input()| or |confirm()|.
+		Only works when the command line is being edited, thus
+		requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
+		Also see |getcmdtype()|, |getcmdline()|, |getcmdpos()|,
+		|setcmdpos()| and |setcmdline()|.
 
 getcmdscreenpos()                                            *getcmdscreenpos()*
 		Return the screen position of the cursor in the command line

runtime/doc/usr_41.txt

@@ -908,7 +908,8 @@ Buffers, windows and the argument list:
 Command line:					*command-line-functions*
 	getcmdcompltype()	get the type of the current command line
 				completion
-	getcmdline()		get the current command line
+	getcmdline()		get the current command line input
+	getcmdprompt()		get the current command line prompt
 	getcmdpos()		get position of the cursor in the command line
 	getcmdscreenpos()	get screen position of the cursor in the
 				command line

runtime/lua/vim/_meta/vimfn.lua

@@ -2883,20 +2883,20 @@ function vim.fn.getcharstr(expr) end
 --- Only works when the command line is being edited, thus
 --- requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
 --- See |:command-completion| for the return string.
---- Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
---- |setcmdline()|.
+--- Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+--- |getcmdprompt()| and |setcmdline()|.
 --- Returns an empty string when completion is not defined.
 ---
 --- @return string
 function vim.fn.getcmdcompltype() end
 
---- Return the current command-line.  Only works when the command
---- line is being edited, thus requires use of |c_CTRL-\_e| or
---- |c_CTRL-R_=|.
+--- Return the current command-line input.  Only works when the
+--- command line is being edited, thus requires use of
+--- |c_CTRL-\_e| or |c_CTRL-R_=|.
 --- Example: >vim
 ---   cmap <F7> <C-\>eescape(getcmdline(), ' \')<CR>
---- <Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()| and
---- |setcmdline()|.
+--- <Also see |getcmdtype()|, |getcmdpos()|, |setcmdpos()|,
+--- |getcmdprompt()| and |setcmdline()|.
 --- Returns an empty string when entering a password or using
 --- |inputsecret()|.
 ---
@@ -2908,12 +2908,22 @@ function vim.fn.getcmdline() end
 --- Only works when editing the command line, thus requires use of
 --- |c_CTRL-\_e| or |c_CTRL-R_=| or an expression mapping.
 --- Returns 0 otherwise.
---- Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()| and
---- |setcmdline()|.
+--- Also see |getcmdtype()|, |setcmdpos()|, |getcmdline()|,
+--- |getcmdprompt()| and |setcmdline()|.
 ---
 --- @return integer
 function vim.fn.getcmdpos() end
 
+--- Return the current command-line prompt when using functions
+--- like |input()| or |confirm()|.
+--- Only works when the command line is being edited, thus
+--- requires use of |c_CTRL-\_e| or |c_CTRL-R_=|.
+--- Also see |getcmdtype()|, |getcmdline()|, |getcmdpos()|,
+--- |setcmdpos()| and |setcmdline()|.
+---
+--- @return string
+function vim.fn.getcmdprompt() end
+
 --- Return the screen position of the cursor in the command line
 --- as a byte count.  The first column is 1.
 --- Instead of |getcmdpos()|, it adds the prompt position.