ytdl-hook: add srv3 to supported subtitle formats

This allows YouTube videos played directly from a URL to make use of
subrandr's SRV3 support.

Author: afishhh

player/lua/ytdl_hook.lua

@@ -79,6 +79,7 @@ local ext_map = {
 
 local codec_map = {
     -- src pattern  = mpv codec
+    ["srv3"]        = "textsub/srv3",
     ["vtt"]         = "webvtt",
     ["opus"]        = "opus",
     ["vp9"]         = "vp9",
@@ -927,7 +928,7 @@ local function run_ytdl_hook(url)
 
     local command = {
         ytdl.path, "--no-warnings", "-J", "--flat-playlist",
-        "--sub-format", "ass/srt/best"
+        "--sub-format", "srv3/ass/srt/best"
     }
 
     -- Checks if video option is "no", change format accordingly,