docs: update example

Author: incendial

example/README.md

@@ -8,7 +8,7 @@ To use Dart Code Metrics as a plugin or a CLI, check out [this repository](https
 
 ## As a library
 
-Dart Code Metrics can be used as a library, imported and called directly from your code. Continue with [this example](https://github.com/dart-code-checker/dart-code-metrics/blob/master/example/example.dart) in order to get more details.
+Dart Code Metrics can be used as a library, imported and called directly from your code. Continue with [this example](https://github.com/dart-code-checker/dart-code-metrics/blob/master/example/lib/main.dart) in order to get more details.
 
 ## Presets
 

example/example.dart renamed to example/lib/main.dart

@@ -24,7 +24,7 @@ Future<void> main() async {
     },
     antiPatterns: {'long-method': {}},
     shouldPrintConfig: false,
-    analysisOptionsPath: '',
+    analysisOptionsPath: null,
   );
 
   const analyzer = LintAnalyzer();

website/docs/getting-started/installation.md

@@ -47,4 +47,4 @@ To use Dart Code Metrics as a command-line tool refer to the [Command Line Inter
 
 ### Library {#library}
 
-To use Dart Code Metrics as a library refer to this [example](https://github.com/dart-code-checker/dart-code-metrics/blob/master/example/example.dart).
+To use Dart Code Metrics as a library refer to this [example](https://github.com/dart-code-checker/dart-code-metrics/blob/master/example/lib/main.dart).