Merge branch 'lazy-reference-extractor' into 'master'

Move Markdown/reference logic from `Gitlab::Markdown` to `Banzai`

- Moves from `Gitlab::Markdown` to `Banzai`
- Moves filters and pipelines into their own namespace: `Banzai::Filter` and `Banzai::Pipeline`
- No more `autoload`!
- Split up `Gitlab::ReferenceExtractor` into `Banzai::ReferenceExtractor` and `Gitlab::ReferenceExtractor`
- Replace `something(load_lazy_references: true)` by `Gitlab::ReferenceExtractor.lazily { something }`

Goes from:

```ruby
def referenced_merge_requests
  references = [self, *notes].flat_map do |note|
    note.all_references(load_lazy_references: false).merge_requests
  end.uniq!

  Gitlab::Markdown::ReferenceFilter::LazyReference.load(references).uniq.sort_by(&:iid)
end
```

to

```ruby
def referenced_merge_requests
  Gitlab::ReferenceExtractor.lazily do
    [self, *notes].flat_map do |note|
      note.all_references.merge_requests
    end
  end.sort_by(&:iid)
end
```

See merge request !2027

1 files changed, 2 insertions, 2 deletions

diff --git a/app/models/note.rb b/app/models/note.rb
index 04053ccc61e..8c5b5836f9a 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -373,11 +373,11 @@ class Note < ActiveRecord::Base
   end
 
   def contains_emoji_only?
-    note =~ /\A#{Gitlab::Markdown::EmojiFilter.emoji_pattern}\s?\Z/
+    note =~ /\A#{Banzai::Filter::EmojiFilter.emoji_pattern}\s?\Z/
   end
 
   def award_emoji_name
-    original_name = note.match(Gitlab::Markdown::EmojiFilter.emoji_pattern)[1]
+    original_name = note.match(Banzai::Filter::EmojiFilter.emoji_pattern)[1]
     AwardEmoji.normilize_emoji_name(original_name)
   end
 end