fix: stricter regex for GH file URL

URL must now include one or more "L"s in its fragment

src/bot/file_preview/mod.rs

@@ -21,7 +21,7 @@ mod gist;
 mod github_repositoriy_file;
 
 static GITHUB_REPOSITORY_FILE_URL_REGEX: Lazy<Regex> = Lazy::new(|| {
-    Regex::new(r"https://github\.com(?:/[^/\s]+){2}/(?:blob|blame)(?:/[^/\s]+)+#[^/\s]+").unwrap()
+    Regex::new(r"https://github\.com(?:/[^/\s]+){2}/(?:blob|blame)(?:/[^/\s]+)+#(?:[^/\s]*L[^/\s]*)+").unwrap()
 });
 
 static GIST_URL_REGEX: Lazy<Regex> =