Simplify long and complex lines

As an alternative to .format(), I have added extra variables.

pkg_resources/__init__.py

@@ -3141,7 +3141,10 @@ def activate(self, path: list[str] | None = None, replace: bool = False) -> None
 
     def egg_name(self):
         """Return what this distribution's standard .egg filename should be"""
-        filename = f"{to_filename(self.project_name)}-{to_filename(self.version)}-py{self.py_version or PY_MAJOR}"
+        name = to_filename(self.project_name)
+        version = to_filename(self.version)
+        py_version = self.py_version or PY_MAJOR
+        filename = f"{name}-{version}-py{py_version}"
 
         if self.platform:
             filename += '-' + self.platform

setuptools/package_index.py

@@ -709,6 +709,9 @@ def gen_setup(self, filename, fragment, tmpdir):
 
         if len(dists) == 1:  # unambiguous ``#egg`` fragment
             basename = os.path.basename(filename)
+            name = dists[0].project_name
+            version = dists[0].version
+            py_modules = os.path.splitext(basename)[0]
 
             # Make sure the file has been downloaded to the temp dir.
             if os.path.dirname(filename) != tmpdir:
@@ -720,7 +723,7 @@ def gen_setup(self, filename, fragment, tmpdir):
             with open(os.path.join(tmpdir, 'setup.py'), 'w', encoding="utf-8") as file:
                 file.write(
                     "from setuptools import setup\n"
-                    f"setup(name={dists[0].project_name!r}, version={dists[0].version!r}, py_modules=[{os.path.splitext(basename)[0]!r}])\n"
+                    f"setup(name={name!r}, version={version!r}, py_modules=[{py_modules!r}])\n"
                 )
             return filename