fix stubgen and add pyi files to package

setup.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 import os
 import sys
+import glob
 import subprocess
 
 from setuptools import setup, Extension, find_packages
@@ -99,6 +100,9 @@ class CMakeBuild(build_ext):
         )
 
 
+# Find stub files
+stubs = [path.replace('quicktex/', '') for path in glob.glob('quicktex/**/*.pyi', recursive=True)]
+
 # The information here can also be placed in setup.cfg - better separation of
 # logic and declaration, and simpler if you include description/version in a file.
 setup(
@@ -113,6 +117,8 @@ setup(
     cmdclass={"build_ext": CMakeBuild},
     packages=find_packages('.'),
     package_dir={'': '.'},
+    package_data={'': ['py.typed'] + stubs},
+    include_package_data=True,
     install_requires=["Pillow", "click"],
     extras_require={
         "tests": ["nose", "parameterized"],

tools/stubgen.py

@@ -40,7 +40,7 @@ if __name__ == "__main__":
 
                 for mod in modules:
                     new_mod = mod.replace(prefix, '')
-                    contents.replace(mod, new_mod)
+                    contents = contents.replace(mod, new_mod)
 
                 # write out to the new location
                 py_module = ext_module.replace(prefix, '')