fixing linting

docs/src/rust/user-guide/getting-started/reading-writing.rs

@@ -2,7 +2,7 @@
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     // --8<-- [start:dataframe]
     use std::fs::File;
-    
+
     use polars::prelude::*;
 
     use chrono::prelude::*;