docs: pulls out variables into separate page (#425)

Author: lukegalbraithrussell

docs/sending-variables.md

@@ -0,0 +1,12 @@
+# Sending variables 
+
+There are different [techniques to send data](/slack-github-action/sending-techniques) into Slack and whichever one is chosen will require a certain set of customized inputs, as described later.
+
+You can provide data to send to Slack from this GitHub Action and either source:
+
+- The default event [context](https://github.com/actions/toolkit/blob/main/packages/github/src/context.ts#L6) with a [payload](https://docs.github.com/en/webhooks/webhook-events-and-payloads) matching the GitHub event.
+- A custom payload with optional [variables](https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables) provided in the GitHub Action step.
+
+These input options are valid for all techniques, but some techniques require specific constraints with certain requirements for valid inputs.
+
+Additional [configurations](/slack-github-action/additional-configurations) and other details are also available for more customizations to the provided payload.

docs/slack-github-action.md

@@ -2,19 +2,6 @@
 
 The GitHub Action for sending data to Slack.
 
-## Sending variables 
-
-There are different [techniques to send data](/slack-github-action/sending-techniques) into Slack and whichever one is chosen will require a certain set of customized inputs, as described later.
-
-You can provide data to send to Slack from this GitHub Action and either source:
-
-- The default event [context](https://github.com/actions/toolkit/blob/main/packages/github/src/context.ts#L6) with a [payload](https://docs.github.com/en/webhooks/webhook-events-and-payloads) matching the GitHub event.
-- A custom payload with optional [variables](https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables) provided in the GitHub Action step.
-
-These input options are valid for all techniques, but some techniques require specific constraints with certain requirements for valid inputs.
-
-Additional [configurations](/slack-github-action/additional-configurations) and other details are also available for more customizations to the provided payload.
-
 ## Versioning
 
 We recommend using the latest version of this GitHub Action for the most recent updates and fixes.