Fix(command_interface): Use comments to generate the help function

The generation part is yet to be done, but the comments itself are
supposed to be the way of documentation.

src/app/command_interface.rs

@@ -22,22 +22,30 @@ use super::events::event_types::Event;
 /// `String` and `()`).
 #[turn_struct_to_ci_commands]
 struct Commands {
+    /// Greets the user
     greet: fn(usize) -> String,
 
-    // Closes the application
+    /// Closes the application
     #[gen_default_lua_function]
     exit: fn(),
+
+    /// Shows the command line
     #[gen_default_lua_function]
     command_line_show: fn(),
+
+    /// Hides the command line
     #[gen_default_lua_function]
     command_line_hide: fn(),
 
+    /// Go to the next plane
     #[gen_default_lua_function]
     cycle_planes: fn(),
+    /// Go to the previous plane
     #[gen_default_lua_function]
     cycle_planes_rev: fn(),
 
-    //// sends a message to the current room
+    /// Send a message to the current room
+    /// The send message is interpreted literally.
     room_message_send: fn(String) -> String,
 }