Some minor fixes to docs

Problem:
Missing subject_label and incorrect asset_name

Solution:
Added subject_label and changed asset_name to asset_label

Signed-off-by: Paul Hewlett <phewlett76@gmail.com>

Author: eccles

docs/runner/events_create.rst

@@ -69,7 +69,7 @@ An example when releasing a software package as an sbom:
       - step:
           action: EVENTS_CREATE
           description: Release YYYYMMDD.1 of Test SBOM for YAML story
-          asset_name: ACME Corporation Detector SAAS
+          asset_label: ACME Corporation Detector SAAS
           print_response: true
         operation: Record
         behaviour: RecordEvidence
@@ -95,7 +95,7 @@ An example when releasing a software package as an sbom attachment:
       - step:
           action: EVENTS_CREATE
           description: Release YYYYMMDD.1 of Test SBOM for YAML story
-          asset_name: ACME Corporation Detector SAAS
+          asset_label: ACME Corporation Detector SAAS
           print_response: true
         operation: Record
         behaviour: RecordEvidence

docs/runner/generic.rst

@@ -53,6 +53,8 @@ Each step follows the same pattern:
 
          assets/add30235-1424-4fda-840a-d5ef82c4c96fa
 
+   when accessing a previously created asset. (i.e. not when creating an asset)
+
 :location_label:
    For location create type actions (LOCATIONS_CREATE_IF_NOT_EXISTS) the label is used
    by the runner to keep track of locations.
@@ -66,4 +68,20 @@ Each step follows the same pattern:
 
          locations/add30235-1424-4fda-840a-d5ef82c4c96fa
 
+   when accessing a previously created location. (i.e. not when creating a location)
+
+:subject_label:
+   For subject create type actions (SUBJECTS_CREATE) the label is used
+   by the runner to keep track of subjects.
+
+   For other actions which require access to a subject, this value is used as a key to
+   obtain the identity of such a previously-created subject.
+
+   In this way one can create subjects and then refer to them in later steps of the story.
+
+   Additionally this label can be an explicit subject identity of the form:
+
+         subjects/add30235-1424-4fda-840a-d5ef82c4c96fa
+
+   when accessing a previously created subject. (i.e. not when creating a subject)