runtime: decouple Open and Launch commands and gx mapping from netrw

closes: #16494
fixes: ##16486

Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/eval.txt

@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 9.1.  Last change: 2025 Jan 02
+*eval.txt*	For Vim version 9.1.  Last change: 2025 Jan 25
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4907,5 +4907,40 @@ executable.  It takes the following arguments:
 	filetype	string
 	executable	string
 
+						      *dist#vim9#Open()* *:Open*
+						      *g:Openprg*
+dist#vim9#Open(file: string) ~
+
+Opens `path` with the system default handler (macOS `open`, Windows
+`explorer.exe`, Linux `xdg-open`, …). If the variable |g:Openprg| exists the
+string specified in the variable is used instead.
+
+NOTE: Escaping of the path is automatically applied.
+
+Usage: >vim
+	:call dist#vim9#Open(<path>)
+	:Open <path>
+<
+
+						  *dist#vim9#Launch()* *:Launch*
+dist#vim9#Launch(file: string) ~
+
+Launches <args> with the appropriate system programs. Intended for launching
+GUI programs within Vim.
+
+NOTE: escaping of <args> is left to the user
+
+Examples: >vim
+	vim9script
+
+	import autoload 'dist/vim9.vim'
+	# Execute 'makeprg' into another xterm window
+	vim9.Launch('xterm ' .. expandcmd(&makeprg))
+<
+
+Usage: >vim
+	:call dist#vim9#Launch(<args>)
+	:Launch <app> <args>.
+<
 
  vim:tw=78:ts=8:noet:ft=help:norl: