DEV: Add specs for hashtags related code (#18526)

Adding a couple of small specs to code around hashtags
for tags and categories since I will be working in this
area soon and these were not covered.

spec/requests/hashtags_controller_spec.rb

@@ -32,6 +32,16 @@ RSpec.describe HashtagsController do
           )
         end
 
+        it "handles tags with the TAG_HASHTAG_POSTFIX" do
+          get "/hashtags.json", params: { slugs: ["#{tag.name}#{PrettyText::Helpers::TAG_HASHTAG_POSTFIX}"] }
+
+          expect(response.status).to eq(200)
+          expect(response.parsed_body).to eq(
+            "categories" => {},
+            "tags" => { tag.name => tag.full_url }
+          )
+        end
+
         it "does not return restricted categories or hidden tags" do
           get "/hashtags.json", params: { slugs: [private_category.slug, hidden_tag.name] }