Fixing a typo in developer-guide.md.

The words 'are' and 'and' were mistyped and need to be switched.

Author: gsfreema

Documentation/project-docs/developer-guide.md

@@ -15,7 +15,7 @@ The CoreCLR repo can be built from a regular, non-admin command prompt. The buil
 | ARM32 | ◯ | ◯| ◯ |
 |       | [Instructions](../building/windows-instructions.md) | [Instructions](../building/linux-instructions.md) | [Instructions](../building/osx-instructions.md) |  
 
-The CoreCLR build and test suite is a work in progress, as are the [building and testing instructions](../README.md). The .NET Core team and the community are improving Linux and OS X support on a daily basis are and adding more tests for all platforms. See [CoreCLR Issues](https://github.com/dotnet/coreclr/issues) to find out about specific work items or report issues.
+The CoreCLR build and test suite is a work in progress, as are the [building and testing instructions](../README.md). The .NET Core team and the community are improving Linux and OS X support on a daily basis and are adding more tests for all platforms. See [CoreCLR Issues](https://github.com/dotnet/coreclr/issues) to find out about specific work items or report issues.
 
 Understanding the TFS-Git Mirror
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