Move IDL version details (#189)

Author: kevmoo

README.md

@@ -67,14 +67,8 @@ definitions:
   the number of breaking changes. This is currently WIP and some members may be
   added or removed.
 
-## Web IDL version
+### Generation
 
-Based on:
-
-<!-- START updated by tool/update_bindings.dart. Do not modify by hand -->
-- @webref/idl [3.43.1](https://www.npmjs.com/package/@webref/idl/v/3.43.1)
-- @webref/css [6.11.0](https://www.npmjs.com/package/@webref/css/v/6.11.0)
-<!-- END updated by tool/update_bindings.dart. Do not modify by hand -->
-
-For instructions on re-generating the DOM bindings, see the
-[generator docs](tool/generator/README.md).
+Most of the APIs in this package are generated from public assets.
+See the [tool directory](https://github.com/dart-lang/web/tree/main/tool) in the
+source repository to learn more.

third_party/mdn/README.md

@@ -10,5 +10,5 @@ See [LICENSE] for the license this content is under.
 
 ## Process
 
-See [../../tool/scrape_mdn.dart] for the script which collects the
-documentation information.
+See [the script](../../tool/scrape_mdn.dart) which collects the documentation
+information.

tool/README.md

@@ -0,0 +1,11 @@
+## Web IDL version
+
+Based on:
+
+<!-- START updated by tool/update_bindings.dart. Do not modify by hand -->
+- @webref/idl [3.43.1](https://www.npmjs.com/package/@webref/idl/v/3.43.1)
+- @webref/css [6.11.0](https://www.npmjs.com/package/@webref/css/v/6.11.0)
+<!-- END updated by tool/update_bindings.dart. Do not modify by hand -->
+
+For instructions on re-generating the DOM bindings, see the
+[generator docs](generator/README.md).

tool/update_bindings.dart

@@ -93,7 +93,7 @@ $_usage''');
 
   // Update readme.
   final readmeFile = File(
-    p.normalize(p.join(_bindingsGeneratorPath, '..', '..', 'README.md')),
+    p.normalize(p.join(_bindingsGeneratorPath, '..', 'README.md')),
   );
 
   final sourceContent = readmeFile.readAsStringSync();