Merge branch 'master' into feature/nullable_microsoft_win32_registry

diff --cc src/libraries/Microsoft.Win32.Registry/ref/Microsoft.Win32.Registry.cs
Simple merge

diff --cc src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
index 4d67950,bca5d38..c477714
--- 1/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
--- 2/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
+++ b/src/libraries/Microsoft.Win32.Registry/src/Microsoft.Win32.Registry.csproj
@@@ -6,10 -6,9 +6,10 @@@
      <IsPartialFacadeAssembly Condition="'$(TargetsNetFx)' == 'true'">true</IsPartialFacadeAssembly>
      <GeneratePlatformNotSupportedAssemblyMessage Condition="'$(TargetsAnyOS)' == 'true' and '$(TargetsNetStandard)' == 'true'">SR.PlatformNotSupported_Registry</GeneratePlatformNotSupportedAssemblyMessage>
      <NoWarn Condition="'$(TargetsUnix)' == 'true'">$(NoWarn);CA1823</NoWarn> <!-- Avoid unused fields warnings in Unix build -->
-     <Nullable>enable</Nullable>
-     <TargetFrameworks>netstandard2.0-Windows_NT;netstandard2.0-Unix;netstandard2.0;net461-Windows_NT;$(NetCoreAppCurrent)-Windows_NT;$(NetCoreAppCurrent)-Unix;$(NetFrameworkCurrent)-Windows_NT</TargetFrameworks>
+     <TargetFrameworks>$(NetCoreAppCurrent)-Windows_NT;$(NetCoreAppCurrent)-Unix;$(NetFrameworkCurrent)-Windows_NT;netstandard2.0-Windows_NT;netstandard2.0-Unix;netstandard2.0;net461-Windows_NT</TargetFrameworks>
      <ExcludeCurrentNetCoreAppFromPackage>true</ExcludeCurrentNetCoreAppFromPackage>
      <ExcludeCurrentFullFrameworkFromPackage>true</ExcludeCurrentFullFrameworkFromPackage>
++    <Nullable>enable</Nullable>
    </PropertyGroup>
    <ItemGroup Condition="'$(TargetsNetFx)' != 'true' and '$(TargetsAnyOS)' != 'true'">
      <Compile Include="$(CommonPath)Interop\Windows\Advapi32\Interop.RegistryConstants.cs">