docs: checklists: Define "wire format"

The phrase is used elsewhere in the document, so be clear about what
is meant.

Change-Id: Idd2cff77d6d52c8e9f6d4397f1f1e97dc9fd26b5
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/docs/checklists/changes.md b/docs/checklists/changes.md
index 685242b..0403509 100644
--- a/docs/checklists/changes.md
+++ b/docs/checklists/changes.md
@@ -44,6 +44,9 @@
 
 - **Public API**: Any definitions and declarations under `include/libpldm`.
 
+- **Wire format**: Any message structure defined in the DMTF PLDM protocol
+  specifications.
+
 ## Elaborations
 
 - Resource exhaustion is always an error condition and never an invariant