Properly detect label reference if followed by period or question mark

app/models/label.rb

@@ -85,10 +85,15 @@ class Label < ActiveRecord::Base
       (#{Project.reference_pattern})?
       #{Regexp.escape(reference_prefix)}
       (?:
-        (?<label_id>\d+(?!\S\w)\b) | # Integer-based label ID, or
+          (?<label_id>\d+(?!\S\w)\b)
+        | # Integer-based label ID, or
           (?<label_name>
-          [A-Za-z0-9_\-\?\.&]+ | # String-based single-word label title, or
-          ".+?"                  # String-based multi-word label surrounded in quotes
+              # String-based single-word label title, or
+              [A-Za-z0-9_\-\?\.&]+
+              (?<!\.|\?)
+            |
+              # String-based multi-word label surrounded in quotes
+              ".+?"
           )
       )
     }x

changelogs/unreleased/dm-label-reference-period.yml

+---
+title: Properly detect label reference if followed by period or question mark
+merge_request:
+author:
+type: fixed

spec/lib/banzai/filter/label_reference_filter_spec.rb

@@ -149,8 +149,8 @@ describe Banzai::Filter::LabelReferenceFilter do
     end
 
     it 'links with adjacent text' do
-      doc = reference_filter("Label (#{reference}).")
-      expect(doc.to_html).to match(%r(\(<a.+><span.+>\?g\.fm&amp;</span></a>\)\.))
+      doc = reference_filter("Label #{reference}.")
+      expect(doc.to_html).to match(%r(<a.+><span.+>\?g\.fm&amp;</span></a>\.))
     end
 
     it 'ignores invalid label names' do