docs(xml): clarify Get/GetByNamespace docs; annotate InternalsVisibleTo

The XML doc summaries on MTConnectVersion.Get and .GetByNamespace were
verbatim copies of each other, obscuring the actual contract: Get takes
a raw XML document (delegating to Namespaces.Get for the extraction
step), GetByNamespace takes an already-resolved namespace URI. Rewrite
each summary to state its own signature and mention the Max-fallback
behavior on GetByNamespace.

Annotate the InternalsVisibleTo grant in MTConnect.NET-XML.csproj so a
future reader sees why the library reaches into MTConnect.NET-XML-Tests
(the tests reach the internal MTConnectVersion / Namespaces helpers,
which have no public equivalent). Also tighten the trailing newline of
MTConnectVersion.cs and update two comment breaks in the test file to
tight em-dashes.

Ultrareview findings F-SIMP-003, F-CR-002, F-CR-004, F-CR-006 (LOW/NIT).

Author: ottobolyos

libraries/MTConnect.NET-XML/MTConnect.NET-XML.csproj

@@ -73,6 +73,7 @@
 	</ItemGroup>
 
 	<ItemGroup>
+		<!-- Grants MTConnect.NET-XML-Tests reach into the internal helpers (MTConnectVersion, Namespaces) that have no public equivalent. The assembly is not strong-named, so no PublicKey clause is required. -->
 		<InternalsVisibleTo Include="MTConnect.NET-XML-Tests" />
 	</ItemGroup>
 

libraries/MTConnect.NET-XML/MTConnectVersion.cs

@@ -8,7 +8,7 @@ namespace MTConnect
     internal static class MTConnectVersion
     {
         /// <summary>
-        /// Gets the Version of the MTConnect standard being used based on the XML Namespace that is used
+        /// Gets the Version of the MTConnect standard from a raw XML document by extracting the root element's namespace URI and dispatching through <see cref="GetByNamespace"/>.
         /// </summary>
         public static Version Get(string xml)
         {
@@ -17,7 +17,7 @@ public static Version Get(string xml)
         }
 
         /// <summary>
-        /// Gets the Version of the MTConnect standard being used based on the XML Namespace that is used
+        /// Gets the Version of the MTConnect standard from an already-resolved namespace URI. Returns <see cref="MTConnectVersions.Max"/> when the namespace is null, empty, or does not match a declared MTConnect namespace.
         /// </summary>
         public static Version GetByNamespace(string ns)
         {
@@ -46,4 +46,4 @@ public static Version GetByNamespace(string ns)
             return MTConnectVersions.Max;
         }
     }
-}
+}