Update api.mdx

Co-authored-by: Benoît Rouleau <[email protected]>

Author: 0xa3k5

website/src/pages/en/subgraphs/developing/creating/graph-ts/api.mdx

@@ -502,7 +502,7 @@ As long as the `ERC20Contract` on Ethereum has a public read-only function calle
 
 Any other contract that is part of the subgraph can be imported from the generated code and can be bound to a valid address. Example of that is presented within the steps below:
 
-- extend `subgraph.yaml` file with desired ABI file:
+- Extend `subgraph.yaml` file with desired ABI file:
 
 ```yaml
 mapping: