Added note on 1 sec freq. for API checks (#1269)

Co-authored-by: Sergii Bezliudnyi <[email protected]>

Author: sujaya-sys

site/content/docs/api-checks/_index.md

@@ -70,6 +70,8 @@ You can configure your checks to run from our [public](/docs/monitoring/global-l
 
 Checkly runs your API checks based on an interval you set. The shortest interval you can run is every 10 seconds and the longest is every 24 hours.
 
+ℹ️ A 1-second interval is available upon request — [contact us](mailto:[email protected]) if you'd like to learn more.
+
 ### Retries & alerting
 
 Select your preferred [retry strategy](/docs/alerting-and-retries/retries/) for failed checks.

site/content/docs/monitoring/_index.md

@@ -13,7 +13,7 @@ menu:
 
 Checkly runs your checks every x minutes, based on an interval you select. We have different minimum intervals for each check type:
 
-- API and network checks can be scheduled to run **every 10 seconds**.
+- API and network checks can be scheduled to run **every 10 seconds** (A 1-second interval is available upon request for API checks — [contact us](mailto:[email protected]) if you'd like to learn more.)
 - Browser and multistep checks can be scheduled to run **every 1 minute**.
 
 You can select one or more data center locations to run your checks from. We advise to **always select at least 2 locations**.