docs: update readme

README.md

@@ -5,15 +5,16 @@
 `config.toml`:
 
 ```toml
-dry_run = true
-out_dir = "./vids"
+dry_run = true                          # set to `false` for real run
+out_dir = "./vids"                      # path to archive vids
 
 [provider]
 [provider.youtube]
-url = "https://www.youtube.com"
-throttle = 1
-video_items = 5
-after_date = "20250326"
+cmd = "./yt-dlp"                        # path to yt-dlp binary
+url = "https://www.youtube.com"         # full yt url
+throttle = 1                            # throttle yt request
+range = "1:5:1"                         # [START][:STOP][:STEP]
+after_date = "20250326"                 # not in use
 ```
 
 `subs-opml.xml`: