Update near accounts docs (#154)

Author: mangas

pages/en/cookbook/near.mdx

@@ -75,6 +75,19 @@ dataSources:
 - NEAR subgraphs introduce a new `kind` of data source (`near`)
 - The `network` should correspond to a network on the hosting Graph Node. On the Hosted Service, NEAR's mainnet is `near-mainnet`, and NEAR's testnet is `near-testnet`
 - NEAR data sources introduce an optional `source.account` field, which is a human-readable ID corresponding to a [NEAR account](https://docs.near.org/docs/concepts/account). This can be an account or a sub-account.
+- NEAR data sources introduce an optional `source.accounts` field, which contains optional suffixes and prefixes.
+At least prefix or suffix must be specified, they will match the any account starting or ending with the list of values respectively. 
+The example below would match: `[app|good].*[morning.near|morning.testnet]`. If only a list of prefixes or suffixes is necessary
+the other field can be omitted.
+```yaml
+      accounts: 
+        prefixes:
+          - app
+          - good
+        suffixes:
+          - morning.near
+          - morning.testnet
+```
 
 NEAR data sources support two types of handlers: