COMMAND DOCS shows module name, where applicable (#10544)

Add field to COMMAND DOCS response to denote the name of the module
that added that command.
COMMAND LIST can filter by module, but if you get the full commands list,
you may still wanna know which command belongs to which module.
The alternative would be to do MODULE LIST, and then multiple calls to COMMAND LIST

tests/unit/moduleapi/cmdintrospection.tcl

@@ -36,6 +36,7 @@ start_server {tags {"modules"}} {
         # Compare the maps. We need to pop "group" first.
         dict unset redis_reply group
         dict unset module_reply group
+        dict unset module_reply module
 
         assert_equal $redis_reply $module_reply
     }

tests/unit/moduleapi/subcommands.tcl

@@ -15,8 +15,8 @@ start_server {tags {"modules"}} {
         set docs_reply [r command docs subcommands.bitarray]
         set docs [dict create {*}[lindex $docs_reply 1]]
         set subcmds_in_cmd_docs [dict create {*}[dict get $docs subcommands]]
-        assert_equal [dict get $subcmds_in_cmd_docs "subcommands.bitarray|get"] {group module}
-        assert_equal [dict get $subcmds_in_cmd_docs "subcommands.bitarray|set"] {group module}
+        assert_equal [dict get $subcmds_in_cmd_docs "subcommands.bitarray|get"] {group module module subcommands}
+        assert_equal [dict get $subcmds_in_cmd_docs "subcommands.bitarray|set"] {group module module subcommands}
     }
 
     test "Module pure-container command fails on arity error" {