Add natvis files for clang/llvm types (#1903)

Should probably get these from the llvm build, but they are not included currently.

Author: duckdoom5

build/premake5.lua

@@ -44,6 +44,7 @@ workspace "CppSharp"
   workspacefiles(path.join(builddir, "premake5.lua"))
   workspacefiles(path.join(builddir, "*.sh"))
   workspacefiles(path.join(rootdir, ".github/workflows/*.yml"))
+  workspacefiles(path.join(rootdir, "*.natvis"))
   workspacefiles(path.join(testsdir, "Test*.props"))
 
   group "Libraries"