Apply suggestions from code review

Co-authored-by: Duncan Dewhurst <[email protected]>

docs/schema/reference.md

@@ -16,7 +16,7 @@ This page presents the release schema in tables, with additional information in
 
 ## Contracting and planning processes
 
-OCDS recognizes two types of processes: contracting processes and planning processes.
+OCDS recognizes two types of processes: contracting processes and planning processes. In OCDS, a given process is uniquely identified by an [open contracting process identifier](identifiers.md#open-contracting-process-identifier-ocid) (`ocid`).
 
 OCDS defines a contracting process as:
 

schema/release-schema.json

@@ -33,7 +33,7 @@
     },
     "tag": {
       "title": "Release Tag",
-      "description": "A tag labeling the release, using the the open [releaseTag](https://standard.open-contracting.org/{{version}}/{{lang}}/schema/codelists/#release-tag) codelist. Tags distinguish, for example, planning and contracting processes and the stages of contracting processes. Codes outside the releaseTag codelist may indicate, for example, the notice or form to which the release corresponds, or the event that triggered the publication of the release. A planning process must use either the 'planning' or 'planningUpdate' code, and must not use any other code from the releaseTag codelist. A contracting process should not use the 'planning' or 'planningUpdate' codes.",
+      "description": "A tag labeling the release, using the open [releaseTag](https://standard.open-contracting.org/{{version}}/{{lang}}/schema/codelists/#release-tag) codelist. Tags distinguish, for example, planning and contracting processes and the stages of contracting processes. Codes outside the releaseTag codelist might indicate, for example, the notice or form to which the release corresponds, or the event that triggered the publication of the release. A planning process must use either the 'planning' or 'planningUpdate' code, and must not use any other code from the releaseTag codelist. A contracting process should not use the 'planning' or 'planningUpdate' codes.",
       "type": "array",
       "items": {
         "type": "string"