Automated rollback of commit 0ff9f3a.

*** Reason for rollback ***

Still broken: https://docs.bazel.build/versions/3.2.0/index.html

*** Original change description ***

Migrate docs.bazel.build to use GitHub Flavored Markdown instead of Kramdown, attempt #2

Rollforward after redirect pages have been fixed by 565f774. Fixes #11451

RELNOTES:
PiperOrigin-RevId: 314304669

scripts/docs/Gemfile

@@ -4,7 +4,3 @@ gem 'pygments.rb', '~> 0.6.0'
 gem 'redcarpet', '~> 3.2', '>= 3.2.3'
 gem 'jekyll-toc', '~> 0.13.1'
 gem 'jekyll-sitemap', '~> 1.4.0'
-
-group :jekyll_plugins do
-  gem 'jekyll-commonmark-ghpages', '~> 0.1.6'
-end

site/_config.yml

@@ -1,5 +1,5 @@
 destination: production
-markdown: CommonMarkGhPages
+markdown: kramdown
 kramdown:
   syntax_highlighter: rouge
   toc_levels: "2,3"
@@ -12,7 +12,6 @@ gems:
   - jekyll-paginate
   - jekyll-toc
   - jekyll-sitemap
-  - jekyll-commonmark-ghpages
 
 url: "https://docs.bazel.build" # used by jekyll-sitemap
 
@@ -67,7 +66,3 @@ toc:
   max_level: 3
   list_class: page-toc
   sublist_class: page-toc-sublist
-
-commonmark:
-  options: ["SMART", "FOOTNOTES"]
-  extensions: ["strikethrough", "autolink", "table", "tagfilter"]