observers.lua: add type annotations for functions

modules/observers.lua

@@ -5,21 +5,29 @@ local fb_utils = require 'modules.utils'
 
 local observers ={}
 
---saves the directory and name of the currently playing file
+---saves the directory and name of the currently playing file
+---@param _ string
+---@param filepath string
 function observers.current_directory(_, filepath)
     directory_movement.set_current_file(filepath)
 end
 
+---@param _ string
+---@param device string
 function observers.dvd_device(_, device)
     if not device or device == "" then device = '/dev/dvd' end
     fb.register_directory_mapping(fb_utils.absolute_path(device), '^dvd://.*', true)
 end
 
+---@param _ string
+---@param device string
 function observers.bd_device(_, device)
     if not device or device == '' then device = '/dev/bd' end
     fb.register_directory_mapping(fb_utils.absolute_path(device), '^bd://.*', true)
 end
 
+---@param _ string
+---@param device string
 function observers.cd_device(_, device)
     if not device or device == '' then device = '/dev/cdrom' end
     fb.register_directory_mapping(fb_utils.absolute_path(device), '^cdda://.*', true)