Fixes formatting error in the rules.md table (#206)

* Fixes formatting error in the rules.md table

The content after the rule `invalid_runtime_check_with_js_interop_types` was not formatted in a table due to syntax error

* Fix multiline descriptions formatting in markdown generation

- Updated the `_createRuleTableRow` function to properly handle multiline descriptions by replacing line breaks with spaces
- Trimmed leading/trailing whitespace and reduced consecutive spaces to a single space
- This ensures that the generated markdown table rows in rules.md are correctly formatted, preventing description content from breaking across lines or having inconsistent spacing

Author: lenzpaul

rules.md

@@ -58,8 +58,7 @@
 | [`empty_statements`](https://dart.dev/lints/empty_statements) | Avoid empty statements. | ✅ |
 | [`exhaustive_cases`](https://dart.dev/lints/exhaustive_cases) | Define case clauses for all constants in enum-like classes. | ✅ |
 | [`implementation_imports`](https://dart.dev/lints/implementation_imports) | Don't import implementation files from another package. |  |
-| [`invalid_runtime_check_with_js_interop_types`](https://dart.dev/lints/invalid_runtime_check_with_js_interop_types) | Avoid runtime type tests with JS interop types where the result may not
-    be platform-consistent. |  |
+| [`invalid_runtime_check_with_js_interop_types`](https://dart.dev/lints/invalid_runtime_check_with_js_interop_types) | Avoid runtime type tests with JS interop types where the result may not be platform-consistent. |  |
 | [`library_prefixes`](https://dart.dev/lints/library_prefixes) | Use `lowercase_with_underscores` when specifying a library prefix. |  |
 | [`library_private_types_in_public_api`](https://dart.dev/lints/library_private_types_in_public_api) | Avoid using private types in public APIs. |  |
 | [`no_leading_underscores_for_library_prefixes`](https://dart.dev/lints/no_leading_underscores_for_library_prefixes) | Avoid leading underscores for library prefixes. | ✅ |

tool/gen_docs.dart

@@ -171,7 +171,10 @@ String _createRuleTableRow(
   if (ruleMeta == null) {
     stderr.writeln("WARNING: Missing rule information for rule: $rule");
   }
-  final description = ruleMeta?['description'] ?? '';
+  final description = (ruleMeta?['description'] ?? '')
+      .replaceAll('\n', ' ')
+      .replaceAll(RegExp(r'\s+'), ' ')
+      .trim();
   final hasFix = ruleMeta?['fixStatus'] == 'hasFix';
   final fixDesc = hasFix ? '✅' : '';