merge: escape \ character in sqlLikeEscape (!529)

View MR for information: https://activitypub.software/TransFem-org/Sharkey/-/merge_requests/529

Approved-by: dakkar <dakkar@thenautilus.net>
Approved-by: Marie <marie@kaifa.ch>

packages/backend/src/misc/sql-like-escape.ts

@@ -4,5 +4,5 @@
  */
 
 export function sqlLikeEscape(s: string) {
-	return s.replace(/([%_])/g, '\\$1');
+	return s.replace(/([%_\\])/g, '\\$1');
 }