fix: check upper bounds of message line numbers for code blocks

lib/processor.js

@@ -331,7 +331,7 @@ function adjustBlock(block) {
 
         const lineInCode = message.line - leadingCommentLines;
 
-        if (lineInCode < 1) {
+        if (lineInCode < 1 || lineInCode >= block.rangeMap.length) {
             return null;
         }
 

tests/lib/processor.js

@@ -755,6 +755,17 @@
             });
         });
 
+        it("should ignore messages after the code block", () => {
+            const empty = [
+                '```javascript',
+                '```',
+            ].join('\n');
+            processor.preprocess(empty, 'empty.md');
+            const message = { message: 'Empty file', ruleId: null, line: 2 };
+            const result = processor.postprocess([[message]], 'empty.md');
+
+            assert.deepStrictEqual(result, []);
+        });
     });
 
     describe("supportsAutofix", () => {