Nicer comments in prepare_distribution_metadata

Why: To improve readability and provide useful context on the "flow".

Author: pradyunsg

src/pip/_internal/distributions/source.py

@@ -24,24 +24,27 @@ def get_pkg_resources_distribution(self):
         return self.req.get_dist()
 
     def prepare_distribution_metadata(self, finder, build_isolation):
-        # Prepare for building. We need to:
-        #   1. Load pyproject.toml (if it exists)
-        #   2. Set up the build environment
+        """Generate metadata for this distribution
+        """
         assert self.req.source_dir
 
+        # Load pyproject.toml, to determine whether PEP 517 is to be used
         self.req.load_pyproject_toml()
+
+        # Set up the build isolation, if this requirement should be isolated
         should_isolate = self.req.use_pep517 and build_isolation
         if should_isolate:
             self._setup_isolation(finder)
 
+        # Generate metadata
         with indent_log():
             self.req.metadata_directory = generate_metadata(self.req)
 
+        # Act on the newly generated metadata, based on the name and version.
         if not self.req.name:
             self.req.move_to_correct_build_directory()
         else:
             self.req.warn_on_mismatching_name()
-
         self.req.assert_source_matches_version()
 
     def _setup_isolation(self, finder):