[Fix] Return MimeCharset as we work with emails...

contrib/google-ced/ced_c.cc

 			ct, ignore_7bit_mail_encodings, bytes_consumed, is_reliable);
 
 	if (IsValidEncoding(enc)) {
-		return EncodingName(enc);
+		return MimeEncodingName(enc);
 	}
 
 	return nullptr;

contrib/google-ced/ced_c.h

 	CED_NUM_CORPA,
 };
 
+/*
+ * XXX: Rspamd addition: it actually returns Mime format of the encoding
+ */
 const char *ced_encoding_detect (const char *text, int text_length,
 								 const char *url_hint,
 								 const char *http_charset_hint,