Swap alt-{left,right,backspace,delete} with ctrl-* on macOS

See https://github.com/fish-shell/fish-shell/issues/ 10926

doc_src/cmds/status.rst

@@ -29,6 +29,7 @@ Synopsis
     status job-control CONTROL_TYPE
     status features
     status test-feature FEATURE
+    status client-os
     status buildinfo
 
 Description
@@ -98,6 +99,10 @@ The following operations (subcommands) are available:
 **test-feature** *FEATURE*
     Returns 0 when FEATURE is enabled, 1 if it is disabled, and 2 if it is not recognized.
 
+**client-os**
+    Print the name of the OS (**bsd**, **macos**, **linux** or **unknown**) that the terminal emulator is running on.
+    When running inside SSH, this will be the client OS.
+
 **buildinfo**
     This prints information on how fish was build - which architecture, which build system or profile was used, etc.
     This is mainly useful for debugging.