FEATURE: whitelist lang attribute

app/assets/javascripts/pretty-text/white-lister.js.es6

@@ -136,6 +136,7 @@ const DEFAULT_LIST = [
   "div.quote-controls",
   "div.title",
   "div[align]",
+  "div[lang]",
   "div[data-*]" /* This may seem a bit much but polls does
                     it anyway and this is needed for themes,
                     special code in sanitizer handles data-*
@@ -170,9 +171,11 @@ const DEFAULT_LIST = [
   "ol",
   "ol[start]",
   "p",
+  "p[lang]",
   "pre",
   "s",
   "small",
+  "span[lang]",
   "span.excerpt",
   "span.hashtag",
   "span.mention",

spec/components/pretty_text_spec.rb

@@ -1307,4 +1307,9 @@ HTML
     expect(cooked).to include("data-theme-a")
   end
 
+  it "whitelists lang attribute" do
+    cooked = PrettyText.cook("<p lang='fr'>tester</p><div lang='fr'>tester</div><span lang='fr'>tester</span>")
+    expect(cooked).to eq("<p lang=\"fr\">tester</p><div lang=\"fr\">tester</div><span lang=\"fr\">tester</span>")
+  end
+
 end