Add to toc

Author: adegeo

docs/fundamentals/toc.yml

@@ -445,6 +445,8 @@ items:
             href: ../standard/datetime/how-to-use-dateonly-timeonly.md
           - name: Perform arithmetic operations
             href: ../standard/datetime/performing-arithmetic-operations.md
+          - name: Use TimeProvider to write predictable code
+            href: ../standard/datetime/timeprovider-overview.md
           - name: "DateTime and DateTimeOffset support in System.Text.Json"
             href: ../standard/datetime/system-text-json-support.md
           - name: Time zones