EC-905 - Document input.snapshot in policy.input

This commit documents the modification that was introduced to the policy
input in #1737 to
include the provided snapshot.

Signed-off-by: robnester-rh <[email protected]>

docs/modules/ROOT/pages/policy_input.adoc

@@ -11,7 +11,7 @@ being available. Not all information is available for all images. This is noted
 description of each attribute.
 
 It is important to note that this command may proccess multiple images at the same time. In such
-cases, a different input is generated for each image. In other words, policy rules only eve have
+cases, a different input is generated for each image. In other words, policy rules only ever have
 access to the information about a single image.
 
 [,json]
@@ -29,6 +29,7 @@ access to the information about a single image.
         }
     ],
     "image": #ImageDescriptor
+    "snapshot": #SnapshotDescriptor
 }
 
 #ImageDescriptor: {
@@ -54,6 +55,19 @@ access to the information about a single image.
         "url": "<STRING>"
     }
 }
+
+#SnapshotDescriptor: {
+    "application": "<STRING>",
+    "displayName": "<STRING>",
+    "displayDescription": "<STRING>",
+    "components": [..."#SnapshotComponentDescriptor"]
+}
+
+#SnapshotComponentDescriptor: {
+    "name": "<STRING>",
+    "containerImage": "<STRING>",
+    "source": #SourceDescriptor"
+}
 ----
 
 `.attestations` is an array of objects. Each object contains the `.statement` and the `.signatures`