Add MSBuildWarnings(Not)As(Errors/Messages)

docs/msbuild/msbuild-reserved-and-well-known-properties.md

@@ -45,6 +45,9 @@ The table in this section shows the MSBuild predefined properties. The example c
 | `MSBuildExtensionsPath` | Well-known | Introduced in the .NET Framework 4: there is no difference between the default values of `MSBuildExtensionsPath` and `MSBuildExtensionsPath32`. You can set the environment variable `MSBUILDLEGACYEXTENSIONSPATH` to a non-null value to enable the behavior of the default value of `MSBuildExtensionsPath` in earlier versions.<br /><br /> In the .NET Framework 3.5 and earlier, the default value of `MSBuildExtensionsPath` points to the path of the MSBuild subfolder under the *\Program Files\\* or *\Program Files (x86)* folder, depending on the bitness of the current process. For example, for a 32-bit process on a 64-bit machine, this property points to the *\Program Files (x86)* folder. For a 64-bit process on a 64-bit machine, this property points to the *\Program Files* folder.<br /><br /> Do not include the final backslash on this property.<br /><br /> This location is a useful place to put custom target files. For example, your target files could be installed at *\Program Files\MSBuild\MyFiles\Northwind.targets* and then imported in project files by using this XML code:<br /><br /> `<Import Project="$(MSBuildExtensionsPath)\MyFiles\Northwind.targets"/>` | `C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild`|
 | `MSBuildExtensionsPath32` | Well-known | The path of the MSBuild subfolder under the *\Program Files* or *\Program Files (x86)* folder. The path always points to the 32-bit *\Program Files (x86)* folder on a 32-bit machine and *\Program Files* on a 64-bit machine.". See also `MSBuildExtensionsPath` and `MSBuildExtensionsPath64`.<br /><br /> Do not include the final backslash on this property. | `C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild`|
 | `MSBuildExtensionsPath64` | Well-known | The path of the MSBuild subfolder under the *\Program Files* folder. For a 64-bit machine, this path always points to the *\Program Files* folder. For a 32-bit machine, this path is blank. See also `MSBuildExtensionsPath` and `MSBuildExtensionsPath32`.<br /><br /> Do not include the final backslash on this property. | `C:\Program Files\MSBuild`|
+| `MSBuildWarningsAsErrors` | Well-known | A list of warning codes to treat as errors. | `MSB1234;MSB5678`|
+| `MSBuildWarningsNotAsErrors` | Well-known | A list of warning codes that should not be promoted to errors even if the `-warnAsError` switch is set to promote all other warnings to errors. Note that it has no effect if that is not true. | `MSB1234;MSB5678`|
+| `MSBuildWarningsAsMessages` | Well-known | A list of warning codes to treat as messages. | `MSB1234;MSB5678`|
 | `MSBuildInteractive` | Reserved | `true` if MSBuild is running interactively, allowing user input. This setting is controlled by the `-interactive` command-line option. | `false` |
 | `MSBuildLastTaskResult` | Reserved | `true` if the previous task completed without any errors (even if there were warnings), or `false` if the previous task had errors. Typically, when an error occurs in a task, the error is the last thing that happens in that project. Therefore, the value of this property is never `false`, except in these scenarios:<br /><br /> - When the `ContinueOnError` attribute of the [Task element (MSBuild)](../msbuild/task-element-msbuild.md) is set to `WarnAndContinue` (or `true`) or `ErrorAndContinue`.<br /><br /> - When the `Target` has an [OnError element (MSBuild)](../msbuild/onerror-element-msbuild.md) as a child element. | `true` |
 | `MSBuildNodeCount` | Reserved | The maximum number of concurrent processes that are used when building. This is the value that you specified for **-maxcpucount** on the command line. If you specified **-maxcpucount** without specifying a value, then `MSBuildNodeCount` specifies the number of processors in the computer. For more information, see [Command-line reference](../msbuild/msbuild-command-line-reference.md) and [Build multiple projects in parallel](../msbuild/building-multiple-projects-in-parallel-with-msbuild.md). | 1 |