[3.14] Use f-strings in csv docs example (GH-135245) (#135285)

Use f-strings in csv docs example (GH-135245)
(cherry picked from commit 2677dd017a033eaaad3b8e1e0eb5664a44e7e231)

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>

Doc/library/csv.rst

@@ -609,7 +609,7 @@ A slightly more advanced use of the reader --- catching and reporting errors::
            for row in reader:
                print(row)
        except csv.Error as e:
-           sys.exit('file {}, line {}: {}'.format(filename, reader.line_num, e))
+           sys.exit(f'file {filename}, line {reader.line_num}: {e}')
 
 And while the module doesn't directly support parsing strings, it can easily be
 done::