fix(no-expression-statements): arrow functions cannot be self returning (#847)

Author: RebeccaStevens

src/rules/no-expression-statements.ts

@@ -150,6 +150,7 @@ function checkExpressionStatement(
           typescript !== undefined &&
           declaration !== undefined &&
           typescript.isFunctionLike(declaration) &&
+          !typescript.isArrowFunction(declaration) &&
           "body" in declaration &&
           declaration.body !== undefined &&
           typescript.isBlock(declaration.body)