Added command failed comments

app/src/main/java/eu/faircode/email/Core.java

@@ -518,11 +518,13 @@ class Core {
                             // Move: NO STORE: mtd: internal error: Cannot set message attributes.<404, ebox: no such entity: LiteMessage 29215 does not exist>
                             // Move: NO mailbox selected READ-ONLY
                             // Move: NO System Error (Failure)
+                            // Move: NO APPEND processing failed.
                             // Add: BAD Data length exceeds limit
                             // Add: NO [LIMIT] APPEND Command exceeds the maximum allowed size
                             // Add: NO APPEND failed: Unknown flag: SEEN
                             // Add: BAD mtd: internal error: APPEND Message too long. 12345678
                             // Add: NO [OVERQUOTA] Not enough disk quota (n.nnn + n.nnn + n.nnn secs).
+                            // Add: NO APPEND failed
                             // Delete: NO [CANNOT] STORE It's not possible to perform specified operation
                             // Delete: NO [UNAVAILABLE] EXPUNGE Backend error
                             // Delete: NO mailbox selected READ-ONLY