Update README.md (microsoft#1954)

Co-authored-by: saschanaz <saschanaz@users.noreply.github.com>

Author: Bashamega

inputfiles/README.md

@@ -3,7 +3,6 @@
 Some files in this directory are generated. Please do not edit them.
 This specifically includes:
 
-* `browser.webidl.preprocessed.json`
 * `idl/*`
 * `mdn/*`