String: tweaks/clanup to character view

Author: dwarfland

Source/Swift.Shared.projitems

@@ -65,7 +65,7 @@
     </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)__Internal.swift" />
     <Compile Include="$(MSBuildThisFileDirectory)Dispatch.swift" />
-    <Compile Include="$(MSBuildThisFileDirectory)Char_Extensions.swift">
+    <Compile Include="$(MSBuildThisFileDirectory)UnicodeScalar_Extensions.swift">
       <VirtualFolder>String</VirtualFolder>
     </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)String.Encoding.swift">