chore: split HierarchicalTextSplitter into companion PR neo4j#548

Remove hierarchical_splitter.py and its tests from this branch (now in PR neo4j#548).
Update example script to reference the companion PR.

Author: jexp

examples/customize/build_graph/components/spacy_kg_pipeline.py

@@ -1,11 +1,15 @@
 # Install: pip install 'neo4j-graphrag[nlp]'
 # Then:    python -m spacy download en_core_web_sm
+#
+# NOTE: HierarchicalTextSplitter is implemented in the companion PR #548.
+# Until that PR is merged, install it from the feat/hierarchical-splitter branch:
+#   pip install git+https://github.com/neo4j/neo4j-graphrag-python@feat/hierarchical-splitter
 """End-to-end SpaCy knowledge-graph pipeline example.
 
 Demonstrates how to wire four pipeline components together without an LLM:
 
     PdfLoader
-        → HierarchicalTextSplitter
+        → HierarchicalTextSplitter  (see PR #548)
         → SpacyEntityRelationExtractor
         → Neo4jWriter
 

src/neo4j_graphrag/experimental/components/text_splitters/__init__.py

@@ -1,23 +0,0 @@
-#  Copyright (c) "Neo4j"
-#  Neo4j Sweden AB [https://neo4j.com]
-#  #
-#  Licensed under the Apache License, Version 2.0 (the "License");
-#  you may not use this file except in compliance with the License.
-#  You may obtain a copy of the License at
-#  #
-#      https://www.apache.org/licenses/LICENSE-2.0
-#  #
-#  Unless required by applicable law or agreed to in writing, software
-#  distributed under the License is distributed on an "AS IS" BASIS,
-#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-#  See the License for the specific language governing permissions and
-#  limitations under the License.
-
-try:
-    from neo4j_graphrag.experimental.components.text_splitters.hierarchical_splitter import (
-        HierarchicalTextSplitter,
-    )
-
-    __all__ = ["HierarchicalTextSplitter"]
-except ImportError:
-    pass