docs/conf.py: fix build failure caused by recent changes to representation of version.

Author: julian-smith-artifex-com

docs/conf.py

@@ -49,19 +49,15 @@
 # built documents.
 #
 # The full version, including alpha/beta/rc tags.
-_path = os.path.abspath(f'{__file__}/../../src/__init__.py')
-with open(_path) as f:
-    for line in f:
-        match = re.search('pymupdf_version = "([0-9][.][0-9]+[.][0-9]+(rc[0-9]+)?)"', line)
-        if match:
-            release = match.group(1)
-            print(f'{__file__}: setting version from {_path}: {release}')
-            break
-    else:
-        raise Exception(f'Failed to find `VersionBind = ...` in {_path}')
-
-# The short X.Y version
-version = release
+
+# PyMuPDF version is set in setup.py, so we import it here.
+sys.path.insert(0, os.path.abspath(f'{__file__}/../..'))
+try:
+    import setup
+finally:
+    del sys.path[0]
+version = setup.version_p
+del setup   # Necessary otherwise sphinx seems to do `setup()`.
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.