Debugger line mapping is off for metadata-namespaced source files

When a source file is assigned a namespace through Studio metadata, Studio compiles it by generating a Namespace ... End Namespace wrapper. Debugger source mapping did not account for those generated wrapper lines, so breakpoints and debugger pauses in namespaced sources could be shifted by one line. In the JSONSerializer repro, moving JSONConvert into the Einhugur namespace made the debugger pause in DeserializeObject() with the current line on a blank line instead of the statement that actually matched the saved breakpoint.