Fix reference pattern for iterations

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/338607

**Problem**

The previous fix for milestone's reference
pattern (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65847)
highlighted a similar problem for Iteration pattern.

**Solution**

Apply the same fix to Iteration reference pattern

Changelog: fixed
EE: true

ee/app/models/ee/iteration.rb

@@ -120,8 +120,8 @@ module EE
             \d+(?!\S\w)\b # Integer-based iteration id, or
           ) |
           (?<iteration_name>
-            [^"\s]+\b |  # String-based single-word iteration title, or
-            "[^"]+"      # String-based multi-word iteration surrounded in quotes
+            [^"\s\<]+\b |  # String-based single-word iteration title, or
+            "[^"]+"        # String-based multi-word iteration surrounded in quotes
           )
         )
       }x.freeze

ee/spec/lib/banzai/filter/references/iteration_reference_filter_spec.rb

@@ -92,6 +92,11 @@ RSpec.describe Banzai::Filter::References::IterationReferenceFilter do
       expect(doc.to_html).to match(%r(\(<a.+>#{iteration.reference_link_text}</a>\.\)))
     end
 
+    it 'links with adjacent html tags' do
+      doc = reference_filter("Iteration <p>#{reference}</p>.")
+      expect(doc.to_html).to match(%r(<p><a.+>#{iteration.reference_link_text}</a></p>))
+    end
+
     it 'ignores invalid iteration names' do
       exp = act = "Iteration #{Iteration.reference_prefix}#{iteration.name.reverse}"
 

ee/spec/models/ee/iteration_spec.rb

@@ -91,6 +91,51 @@ RSpec.describe Iteration do
     end
   end
 
+  describe '.reference_pattern' do
+    subject { described_class.reference_pattern }
+
+    let(:captures) { subject.match(reference).named_captures }
+
+    context 'when iteration id is provided' do
+      let(:reference) { 'gitlab-org/gitlab-ce*iteration:123' }
+
+      it 'correctly detects the iteration' do
+        expect(captures).to eq(
+          'namespace' => 'gitlab-org',
+          'project' => 'gitlab-ce',
+          'iteration_id' => '123',
+          'iteration_name' => nil
+        )
+      end
+    end
+
+    context 'when iteration name is provided' do
+      let(:reference) { 'gitlab-org/gitlab-ce*iteration:my-iteration' }
+
+      it 'correctly detects the iteration' do
+        expect(captures).to eq(
+          'namespace' => 'gitlab-org',
+          'project' => 'gitlab-ce',
+          'iteration_id' => nil,
+          'iteration_name' => 'my-iteration'
+        )
+      end
+    end
+
+    context 'when reference includes tags' do
+      let(:reference) { '<p>gitlab-org/gitlab-ce*iteration:my-iteration</p>' }
+
+      it 'correctly detects the iteration' do
+        expect(captures).to eq(
+          'namespace' => 'gitlab-org',
+          'project' => 'gitlab-ce',
+          'iteration_id' => nil,
+          'iteration_name' => 'my-iteration'
+        )
+      end
+    end
+  end
+
   describe '.filter_by_state' do
     let_it_be(:closed_iteration) { create(:iteration, :closed, :skip_future_date_validation, group: group, start_date: 8.days.ago, due_date: 2.days.ago) }
     let_it_be(:current_iteration) { create(:iteration, :current, :skip_future_date_validation, group: group, start_date: 1.day.ago, due_date: 6.days.from_now) }