Add explicit polars overloads

Author: J-Meyers

_duckdb-stubs/__init__.pyi

@@ -318,7 +318,11 @@ class DuckDBPyConnection:
     def list_type(self, type: sqltypes.DuckDBPyType) -> sqltypes.DuckDBPyType: ...
     def load_extension(self, extension: str) -> None: ...
     def map_type(self, key: sqltypes.DuckDBPyType, value: sqltypes.DuckDBPyType) -> sqltypes.DuckDBPyType: ...
-    def pl(self, rows_per_batch: pytyping.SupportsInt = 1000000, *, lazy: bool = False) -> polars.DataFrame: ...
+    @pytyping.overload
+    def pl(self, rows_per_batch: pytyping.SupportsInt = 1000000, *, lazy: pytyping.Literal[False] = ...) -> polars.DataFrame: ...
+    @pytyping.overload
+    def pl(self, rows_per_batch: pytyping.SupportsInt = 1000000, *, lazy: pytyping.Literal[True]) -> polars.LazyFrame: ...
+    def pl(self, rows_per_batch: pytyping.SupportsInt = 1000000, *, lazy: bool = False) -> pytyping.Union[polars.DataFrame, polars.LazyFrame]: ...
     def query(self, query: str, *, alias: str = "", params: object = None) -> DuckDBPyRelation: ...
     def query_progress(self) -> float: ...
     def read_csv(