Update MD045/no-alt-text to allow violations when an HTML IMG has aria-hidden set to true (fixes #1576).

test/snapshots/markdownlint-test-scenarios.mjs.md

@@ -42681,6 +42681,22 @@ Generated by [AVA](https://avajs.dev).
             'no-alt-text',
           ],
         },
+        {
+          errorContext: null,
+          errorDetail: null,
+          errorRange: [
+            24,
+            42,
+          ],
+          fixInfo: null,
+          lineNumber: 75,
+          ruleDescription: 'Images should have alternate text (alt text)',
+          ruleInformation: 'https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/md045.md',
+          ruleNames: [
+            'MD045',
+            'no-alt-text',
+          ],
+        },
       ],
       fixed: `# Images with and without alternate text␊
       ␊
@@ -42752,6 +42768,18 @@ Generated by [AVA](https://avajs.dev).
         <img src="image.png" /> {MD045}␊
       </p>␊
       ␊
+      No alt attribute is okay when the image is hidden from assistive technology:␊
+      <img src="image.png" aria-hidden="true"/>␊
+      <img src="image.png" ARIA-HIDDEN="TRUE" />␊
+      ␊
+      But not when disabled: <img src="image.png" aria-hidden="false"/> {MD045}␊
+      ␊
+      Multi-line image tag aria-hidden:␊
+      <img␊
+        src="image.png"␊
+        aria-hidden="true"␊
+        />␊
+      ␊
       <!-- markdownlint-restore no-inline-html -->␊
       ␊
       [notitle]: image.jpg␊