Fixed spelling error

synergy -> synergy

Author: jongalloway

docs/core/preview3/tools/extensibility.md

@@ -142,7 +142,7 @@ Consuming custom targets is done by providing a `<PackageReference>` that points
 
 Using the custom target depends solely on how you configure it. Since it is the usual MSBuild target, it can depend on a given target, run after another target and can also be manually invoked using the `dotnet msbuild /t:<target-name>` command. 
 
-However, if you wish to provide a better user experience to your users, you can combine per-project tools and custom targets. In this scenario, the per-project tool would essentially just accept whatever needed parameters and would translate that into the required `dotnet msbuild` invocation that would execute the target. You can see a sample of this kind of sinergy on the [MVP Summit 2016 Hackathon samples](https://github.com/dotnet/MVPSummitHackathon2016) repo in the [`dotnet-packer`](https://github.com/dotnet/MVPSummitHackathon2016/tree/master/dotnet-packer) project. 
+However, if you wish to provide a better user experience to your users, you can combine per-project tools and custom targets. In this scenario, the per-project tool would essentially just accept whatever needed parameters and would translate that into the required `dotnet msbuild` invocation that would execute the target. You can see a sample of this kind of synergy on the [MVP Summit 2016 Hackathon samples](https://github.com/dotnet/MVPSummitHackathon2016) repo in the [`dotnet-packer`](https://github.com/dotnet/MVPSummitHackathon2016/tree/master/dotnet-packer) project. 
 
 ### PATH-based extensibility
 PATH-based extensibility is usually used for development machines where you need a tool that conceptually covers more