Removed restricted mode - Fix #11972

runtime/doc/cmdline.txt

@@ -973,7 +973,7 @@ name).  This is included for backwards compatibility with version 3.0, the
 
 Note: Where a file name is expected wildcards expansion is done.  On Unix the
 shell is used for this, unless it can be done internally (for speed).
-Unless in |restricted-mode|, backticks work also, like in >
+Backticks work also, like in >
 	:n `echo *.c`
 But expansion is only done if there are any wildcards before expanding the
 '%', '#', etc..  This avoids expanding wildcards inside a file name.  If you

runtime/doc/diff.txt

@@ -20,8 +20,8 @@ additionally sets up for viewing the differences between the arguments. >
 
 	nvim -d file1 file2 [file3 [file4]]
 
-In addition to the |-d| argument, |-Z| and |-R| may be used for restricted
-mode and readonly mode respectively.
+In addition to the |-d| argument, |-R| may be used for readonly mode
+respectively.
 
 The second and following arguments may also be a directory name.  Vim will
 then append the file name of the first argument to the directory name to find

runtime/doc/eval.txt

@@ -5698,7 +5698,6 @@ libcall({libname}, {funcname}, {argument})
 		If {argument} is a number, it is passed to the function as an
 		int; if {argument} is a string, it is passed as a
 		null-terminated string.
-		This function will fail in |restricted-mode|.
 
 		libcall() allows you to write your own 'plug-in' extensions to
 		Vim without having to recompile the program.  It is NOT a
@@ -8804,7 +8803,6 @@ system({cmd} [, {input}])				*system()* *E677*
 		{cmd} is a string: 'shell' 'shellcmdflag' {cmd}
 
 		The resulting error code can be found in |v:shell_error|.
-		This function will fail in |restricted-mode|.
 
 		Note that any wrong value in the options mentioned above may
 		make the function fail.  It has also been reported to fail

runtime/doc/starting.txt

@@ -185,18 +185,6 @@ argument.
 		the 'modifiable' and 'write' options can be set to enable
 		changes and writing.
 
-					*-Z* *restricted-mode* *E145* *E981*
--Z		Restricted mode.  All commands that make use of an external
-		shell are disabled.  This includes suspending with CTRL-Z,
-		":sh", filtering, the system() function, backtick expansion
-		and libcall().
-		Also disallowed are delete(), rename(), mkdir(), jobstart(),
-		etc.
-		Interfaces, such as Python, Ruby and Lua, are also disabled,
-		since they could be used to execute shell commands.
-		Note that the user may still find a loophole to execute a
-		shell command, it has only been made difficult.
-
 -e							*-e* *-E*
 -E		Start Nvim in Ex mode |gQ|.