Open the text file, then press Control + F to search. Enter Miracast into the search box, then click on Find Next. You should have 3 results, and you will want to see that Miracast is listed as available or supported for the first 2 results.
This can be done using the DxDiag tool on your computer. Open your Start menu and type dxdiag into the Run box. This will open a diagnostic window on your computer. Click on the Save All Information button and save the text file that this tool creates somewhere accessible, such as your Desktop.