Update private-files.md (#1853)

Author: Purukitto

src/_guides/libraries/private-files.md

@@ -76,8 +76,8 @@ consider using a global ignore file
 When you use pub from within a Git repo,
 pub ignores the same files that Git does.
 For example, if you run `pub publish` from a Git repo
-that has a `.gitignore` file containing `*.js`,
-then your published package won't contain `*.js` files.
+that has a `.gitignore` file containing `keys.txt`,
+then your published package won't contain the `keys.txt` file.
 
 For more information on `.gitignore` files,
 see the GitHub help page
@@ -102,19 +102,3 @@ similar to Ruby's `Gemfile.lock`.
 **For application packages**, **do** commit `pubspec.lock`.
 This file is the recommended way for non-shared resources
 such as applications to manage their dependencies.
-
-### *.js
-
-Don't commit JavaScript files generated by dart2js. Just be careful
-that you don't accidentally exclude source files written in JavaScript.
-
-Calling dart2js without any flags generates `out.js`, but the
-tools that invoke dart2js often specify an output name, such as:
-
-{% prettify none  %}
-dart2js -o main.dart.js main.dart
-{% endprettify %}
-
-For more information on generating and debugging
-JavaScript source for Dart apps, see the
-[dart2js documentation](/tools/dart2js).