Add regression test for trailing backslash in text role

Author: lacatoire

packages/guides-restructured-text/tests/unit/Parser/Productions/InlineRules/TextRoleRuleTest.php

@@ -148,4 +148,31 @@ public function __construct(
          */
         self::assertSame($expectedRawContent, $node->rawContent);
     }
+
+    public function testApplyReturnsNullOnTrailingBackslashWithoutRaisingWarning(): void
+    {
+        $input = ":role:`text\\";
+
+        $textRoleFactory = $this->createMock(TextRoleFactory::class);
+        $textRoleFactory->expects(self::never())->method('getTextRole');
+
+        $lexer = new InlineLexer();
+        $lexer->setInput($input);
+        $lexer->moveNext();
+        $lexer->moveNext();
+
+        $textRoleRule = new TextRoleRule();
+        self::assertTrue($textRoleRule->applies($lexer));
+
+        $documentParserContext = new DocumentParserContext(
+            self::createStub(ParserContext::class),
+            $textRoleFactory,
+            self::createStub(MarkupLanguageParser::class),
+        );
+
+        self::assertNull($textRoleRule->apply(
+            new BlockContext($documentParserContext, ''),
+            $lexer,
+        ));
+    }
 }