web/DonateOptionsCard: rename monthly to recurring

web/i18n/en/donate.json

@@ -6,7 +6,7 @@
     "body.keep_going": "you can help us stay motivated & keep creating safe alternatives to abusive tools by sharing cobalt with a friend or donating.",
 
     "card.once": "one-time donation",
-    "card.monthly": "monthly donation",
+    "card.recurring": "recurring donation",
     "card.custom": "custom amount (from $2)",
 
     "card.processor": "processed by {{value}}",