docs: use correct capitalization for "Datadog" in navigation sidebar (#…

…2809)

See DataDog/documentation#8028 for more context.

Signed-off-by: Kyle Smith <knksmith57@gmail.com>

mkdocs.yml

@@ -59,7 +59,7 @@ nav:
   - Overview: features/analysis.md
   - Plugins: analysis/plugins.md
   - Prometheus: analysis/prometheus.md
-  - DataDog: analysis/datadog.md
+  - Datadog: analysis/datadog.md
   - NewRelic: analysis/newrelic.md
   - Wavefront: analysis/wavefront.md
   - Job: analysis/job.md