Update docs/html/reference/installation-report.md

Co-authored-by: Pradyun Gedam <[email protected]>

Author: sbidoul

docs/html/reference/installation-report.md

@@ -27,6 +27,8 @@ The report is a JSON object with the following properties:
   markers](https://peps.python.org/pep-0508/#environment-markers) for more information.
   Values have a string type.
 
+(InstallationReportItem)=
+
 An `InstallationReportItem` is an object describing a (to be) installed distribution
 package with the following properties: