_ViewImport.cshtml changes do not immediately show in affected Razor files

[NTaylorMullen]

Today when making changes in _ViewImport.cshtml changes are not reflected in the affected Razor files until a full re-parse occurs.

For instance when adding @addTagHelperPrefix "th:" TagHelpers that existed prior to the directive still show up in the editor until you start typing new HTML elements, new C# bits, delete anything, or close/reopen cshtml file.