applying feedback for payment account limits

Author: ntombing

docs/topics/merchants/online/cards/index.mdx

@@ -12,7 +12,7 @@ Accepting card payments is in private beta.
 
 Cards are the most common way for customers worldwide to pay.
 Swan supports most major card issuers, including Visa, Mastercard, and *Cartes Bancaires* (CB) in France.
-AmericanExpress isn't supported.
+American Express isn't supported.
 
 Merchants can use payment links to accept payments from cardholders anywhere.
 Collect rent, share invoices, and accept customer payments through a Swan merchant account.

docs/topics/merchants/online/sdd/index.mdx

@@ -78,7 +78,7 @@ import RollingReserve from '../../partials/_rolling-reserve.mdx';
 | SEPA Direct Debit - B2B | ✓ **Yes** | 100% over 3 business days |
 
 ## Payment amount limit {#payment-limit}
-For security and risk management, Swan may apply a **payment amount limit** to single SEPA Direct Debit (SDD) payment. 
+For security and risk management, Swan may apply a **payment amount limit** to a single SEPA Direct Debit (SDD) payment. 
 This limit defines the maximum amount a user can spend in one SDD transaction. 
 If a payment **exceeds this limit**, the API returns a `ForbiddenRejection` error.