Generate SrcSpan for cached files in plugin

Profile traces (enter/exit markers) include the function name and source span of the function definition. This source span data is retrieved from GHC's Name information. This works when no files are cached and GHC runs on every used file. However, when GHC caches files, it does not provide source span information for cached unfoldings, resulting in profile traces lacking source span data.

We need to determine a method for either enabling GHC to provide source span information for functions defined in cached files, or implementing this functionality manually within the plugin. The former approach appears more promising.

source span annotation for hoisted functions also have this problem