Document supported pattern syntax in Lists

Lists.md

@@ -88,6 +88,30 @@ Delete the line from `whitelist` and commit. The next sync will re-add
 the entry to the blacklist if upstream still has it. If upstream no longer
 has the entry, the entry stays gone (which is probably what you want).
 
+## Pattern syntax
+
+Each line in `blacklist` and `whitelist` is a pattern. The forms supported
+are the same forms that qBittorrent's excluded file names accepts, since
+that is where blacklist patterns ultimately end up via Cleanuparr's
+Blocklist Sync:
+
+| Form | Example | Matches |
+|---|---|---|
+| `*example` | `*.srt` | File name ends with `example` |
+| `example*` | `sample*` | File name starts with `example` |
+| `*example*` | `*sample*` | File name contains `example` |
+| `example` | `RARBG.txt` | File name is exactly `example` |
+| `regex:<regex>` | `regex:.*\.srt$` | File name matches the regex |
+
+Cleanuparr's Malware Blocker accepts the same forms when reading the
+whitelist for Sonarr/Radarr queue inspection, so a single set of pattern
+forms covers both consumers.
+
+The forms are not interchangeable from the merge script's point of view.
+`*.srt` and `regex:.*\.srt$` describe the same set of files but are
+different strings. The whitelist subtraction (next section) is exact-string,
+so picking one form and using it consistently in both files matters.
+
 ## Pattern matching
 
 The whitelist-to-blacklist exclusion uses **exact-string set subtraction**,