Add @sharwell to codeowners (#3070)

* Add @sharwell to codeowners

- @sharwell this would mean you're auto-included on all PR reviews. If this is something you're not interested in to avoid the noise let me know

* Use Razor tooling team.

.github/CODEOWNERS

@@ -7,4 +7,4 @@
 /eng/common/                                   @dotnet-maestro-bot @dougbu
 /eng/Versions.props                            @dotnet-maestro-bot @dougbu
 /eng/Version.Details.xml                       @dotnet-maestro-bot @dougbu
-/src/Razor/                                    @NTaylorMullen @ryanbrandenburg @TanayParikh @allisonchou
+/src/Razor/                                    @dotnet/razor-tooling