message: fix plugin example.
diff: @@ -230,21 +230,19 @@ Diagnostics must run every time it is relevant:
  Note: in a language-server context, Scope validation happens every time a file changes.
  ```typescript
  -// myDiagnosticPlugin.ts
  -import { CompilerPlugin, BrsFile, XmlFile } from 'brighterscript';
  -import { isBrsFile } from 'brighterscript/dist/parser/ASTUtils';
  +// bsc-plugin-no-underscores.ts
  +import { CompilerPlugin, BscFile } from 'brighterscript';
  +import { isBrsFile } from 'brighterscript';
  // plugin factory
  export default function () {
  return {
  - name: 'myDiagnosticPlugin',
  + name: 'no-underscores',
  // post-parsing validation
  afterFileValidate: (file: BscFile) => {
  - if (!isBrsFile(file)) {
  - return;
  - }
  + if (isBrsFile(file)) {
  // visit function statements and validate their name
  - file.parser.functionStatements.forEach((fun) => {
  + file.parser.references.functionStatements.forEach((fun) => {
  if (fun.name.text.includes('_')) {
  file.addDiagnostics([{
  code: 9000,
  @@ -255,6 +253,7 @@ export default function () {
  }
  });
  }
  + }
  } as CompilerPlugin;
  };
  ```
  