Fix typo in README.md

README.md

@@ -40,7 +40,7 @@ pub fn main() {
   "  -123  " |> lenient_parse.to_int |> io.debug
   // Ok(-123)
 
-  // Parse a string containing an integer with an underscores
+  // Parse a string containing an integer with underscores
   "1_000_000" |> lenient_parse.to_int |> io.debug
   // Ok(1000000)
 }