Remove file type from toc href

Author: wadepickett

docs/navigate/tools-diagnostics/toc.yml

@@ -403,7 +403,7 @@ items:
               - name: .NET extensions metrics
                 href: ../../core/diagnostics/built-in-metrics-diagnostics.md
               - name: ASP.NET Core metrics
-                href: /aspnet/core/log-mon/metrics/built-in.md
+                href: /aspnet/core/log-mon/metrics/built-in
               - name: System.Net metrics
                 href: ../../core/diagnostics/built-in-metrics-system-net.md
           - name: EventCounters