docs: add module-level docstrings to staticfiles and templating modules

Documents the re-export modules for Starlette's StaticFiles and
Jinja2Templates, clarifying their purpose for new contributors.

fastapi/staticfiles.py

@@ -1 +1,8 @@
+"""
+Static file serving for FastAPI.
+
+Re-exports Starlette's StaticFiles class for serving static files
+(CSS, JavaScript, images) in FastAPI applications.
+"""
+
 from starlette.staticfiles import StaticFiles as StaticFiles  # noqa

fastapi/templating.py

@@ -1 +1,8 @@
+"""
+Template rendering for FastAPI.
+
+Re-exports Starlette's Jinja2Templates class for server-side rendering
+with Jinja2 templates in FastAPI applications.
+"""
+
 from starlette.templating import Jinja2Templates as Jinja2Templates  # noqa