Assert Reference Manual generated content is in sync with template (hazelcast#1351)

`Reference_Manual.md.in` is a template used to generate
`Reference_Manual.md` content.

In hazelcast#1339, both
files were changed, but not kept in sync - as such, the content of
`Reference_Manual.md` is outdated.

Changes:
- added validation to PR builder that the generated
`Reference_Manual.md` matches what's in the PR
- [_example_ of the output produces when it
fails](https://github.com/hazelcast/hazelcast-cpp-client/actions/runs/19048201782)
- updated `Reference_Manual.md` to address the original issue

Author: JackPGreen

.github/workflows/build-pr.yml

@@ -115,6 +115,16 @@ jobs:
           AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
           HZ_TEST_AWS_INSTANCE_PRIVATE_IP: ${{ secrets.HZ_TEST_AWS_INSTANCE_PRIVATE_IP }}
 
+        # Tagged onto another build to avoid re-running the entire build to check separately
+      - name: Check Reference Manual generated correctly
+        run: |
+          if ! git diff --quiet ${OUTPUT_REFERENCE_MANUAL_FILE}; then
+            echo "::error file=${OUTPUT_REFERENCE_MANUAL_FILE}::File does not match generated version from template"
+            exit 1
+          fi
+        env:
+          OUTPUT_REFERENCE_MANUAL_FILE: Reference_Manual.md
+
   shared-matrix:
     uses: ./.github/workflows/get-shared-matrix.yml