fix typo

Author: zariiii9003

can/io/printer.py

@@ -33,7 +33,7 @@ def __init__(
         """
         :param file: An optional path-like object or a file-like object to "print"
                      to instead of writing to standard out (stdout).
-                     If this is a file-like object, is has to be opened in text
+                     If this is a file-like object, it has to be opened in text
                      write mode, not binary write mode.
         :param append: If set to `True` messages, are appended to the file,
                        else the file is truncated