Change OSX to macOS in error message (#12756)

Author: JamesNK

src/ProjectTemplates/test/GrpcTemplateTest.cs

@@ -44,7 +44,7 @@ public async Task GrpcTemplate()
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                 {
                     Assert.True(serverProcess.Process.HasExited, "built");
-                    Assert.Contains("System.NotSupportedException: HTTP/2 over TLS is not supported on OSX due to missing ALPN support.",
+                    Assert.Contains("System.NotSupportedException: HTTP/2 over TLS is not supported on macOS due to missing ALPN support.",
                         ErrorMessages.GetFailedProcessMessageOrEmpty("Run built service", Project, serverProcess.Process));
                 }
                 else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && Environment.OSVersion.Version < new Version(6, 2))
@@ -68,7 +68,7 @@ public async Task GrpcTemplate()
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
                 {
                     Assert.True(aspNetProcess.Process.HasExited, "published");
-                    Assert.Contains("System.NotSupportedException: HTTP/2 over TLS is not supported on OSX due to missing ALPN support.",
+                    Assert.Contains("System.NotSupportedException: HTTP/2 over TLS is not supported on macOS due to missing ALPN support.",
                         ErrorMessages.GetFailedProcessMessageOrEmpty("Run published service", Project, aspNetProcess.Process));
                 }
                 else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && Environment.OSVersion.Version < new Version(6, 2))

src/Servers/Kestrel/Core/src/CoreStrings.resx

@@ -606,7 +606,7 @@ For more information on configuring HTTPS see https://go.microsoft.com/fwlink/?l
     <value>The request trailers are not available yet. They may not be available until the full request body is read.</value>
   </data>
   <data name="HTTP2NoTlsOsx" xml:space="preserve">
-    <value>HTTP/2 over TLS is not supported on OSX due to missing ALPN support.</value>
+    <value>HTTP/2 over TLS is not supported on macOS due to missing ALPN support.</value>
   </data>
   <data name="HTTP2NoTlsWin7" xml:space="preserve">
     <value>HTTP/2 over TLS is not supported on Windows 7 due to missing ALPN support.</value>

src/Servers/Kestrel/test/FunctionalTests/Http2/HandshakeTests.cs

@@ -53,7 +53,7 @@ public void TlsAndHttp2NotSupportedOnMac()
                 });
             }));
 
-            Assert.Equal("HTTP/2 over TLS is not supported on OSX due to missing ALPN support.", ex.Message);
+            Assert.Equal("HTTP/2 over TLS is not supported on macOS due to missing ALPN support.", ex.Message);
         }