Add Azure Function Key to docs (#36437)

Co-authored-by: Anne-Marie <102995847+am-stead@users.noreply.github.com>

data/secret-scanning.yml

@@ -258,6 +258,19 @@
   hasPushProtection: true
   hasValidityCheck: false
 
+- provider: 'Azure'
+  supportedSecret: 'Azure Function Key'
+  secretType: 'azure_function_key'
+  versions:
+    fpt: '*'
+    ghec: '*'
+    ghes: '>=3.5'
+    ghae: '>=3.5'
+  isPublic: true
+  isPrivateWithGhas: true
+  hasPushProtection: true
+  hasValidityCheck: false
+
 - provider: 'Azure'
   supportedSecret: 'Azure ML Studio (classic) Web Service Key'
   secretType: 'azure_ml_web_service_classic_identifiable_key'