re-enable linting for the core package (#7677)

* re-enable linting for the core package

* fix docstring

Author: masci

Diff for: .github/workflows/linting.yml

@@ -8,7 +8,6 @@ on:
       - "test/**/*.py"
       - "e2e/**/*.py"
       - "pyproject.toml"
-      - "!haystack/core/**/*.py"
 
 env:
   PYTHON_VERSION: "3.8"

Diff for: haystack/core/pipeline/descriptions.py

@@ -16,8 +16,9 @@ def find_pipeline_inputs(
     graph: networkx.MultiDiGraph, include_connected_sockets: bool = False
 ) -> Dict[str, List[InputSocket]]:
     """
-    Collect components that have disconnected/connected input sockets. Note that this method returns *ALL*
-    disconnected input sockets, including all such sockets with default values.
+    Collect components that have disconnected/connected input sockets.
+
+    Note that this method returns *ALL* disconnected input sockets, including all such sockets with default values.
     """
     return {
         name: [