Update micromark code and tests for prior commit updating markdownlint-micromark (including micromark to 3.2.0).

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

@@ -1628,7 +1628,7 @@ Generated by [AVA](https://avajs.dev).
             endLine: 21,
             startColumn: 3,
             startLine: 21,
-            text: null,
+            text: '',
             type: 'blockQuote',
           },
         ],
@@ -1636,7 +1636,7 @@ Generated by [AVA](https://avajs.dev).
         endLine: 21,
         startColumn: 1,
         startLine: 20,
-        text: null,
+        text: '',
         type: 'blockQuote',
       },
       {
@@ -1974,7 +1974,7 @@ Generated by [AVA](https://avajs.dev).
             endLine: 28,
             startColumn: 3,
             startLine: 25,
-            text: null,
+            text: '',
             type: 'listUnordered',
           },
         ],
@@ -1982,7 +1982,7 @@ Generated by [AVA](https://avajs.dev).
         endLine: 28,
         startColumn: 1,
         startLine: 23,
-        text: null,
+        text: '',
         type: 'listUnordered',
       },
       {
@@ -2347,7 +2347,7 @@ Generated by [AVA](https://avajs.dev).
             endLine: 35,
             startColumn: 4,
             startLine: 32,
-            text: null,
+            text: '',
             type: 'listOrdered',
           },
         ],
@@ -2355,7 +2355,7 @@ Generated by [AVA](https://avajs.dev).
         endLine: 35,
         startColumn: 1,
         startLine: 30,
-        text: null,
+        text: '',
         type: 'listOrdered',
       },
       {