Revert "Drop reportlab warning shim"

This reverts commit 162a47f.

src/ocrmypdf/hocrtransform.py

@@ -11,14 +11,20 @@
 import argparse
 import os
 import re
+import warnings
 from math import atan, cos, sin
 from pathlib import Path
 from typing import Any, NamedTuple
 from xml.etree import ElementTree
 
-from reportlab.lib.colors import black, cyan, magenta, red
-from reportlab.lib.units import inch
-from reportlab.pdfgen.canvas import Canvas
+with warnings.catch_warnings():
+    # reportlab uses deprecated load_module
+    warnings.filterwarnings(
+        'ignore', category=DeprecationWarning, message=r".*load_module.*"
+    )
+    from reportlab.lib.colors import black, cyan, magenta, red
+    from reportlab.lib.units import inch
+    from reportlab.pdfgen.canvas import Canvas
 
 # According to Wikipedia these languages are supported in the ISO-8859-1 character
 # set, meaning reportlab can generate them and they are compatible with hocr,