fix: Document Classifiers - fix error messages (#8765)

* fix: Document Classifiers - fix docstrings + error messages

* grammar

* fix

Author: anakin87

haystack/components/classifiers/document_language_classifier.py

@@ -83,7 +83,7 @@ def run(self, documents: List[Document]):
         if not isinstance(documents, list) or documents and not isinstance(documents[0], Document):
             raise TypeError(
                 "DocumentLanguageClassifier expects a list of Document as input. "
-                "In case you want to classify a text, please use the TextLanguageClassifier."
+                "In case you want to classify and route a text, please use the TextLanguageRouter."
             )
 
         output: Dict[str, List[Document]] = {language: [] for language in self.languages}

haystack/components/classifiers/zero_shot_document_classifier.py

@@ -211,8 +211,8 @@ def run(self, documents: List[Document], batch_size: int = 1):
 
         if not isinstance(documents, list) or documents and not isinstance(documents[0], Document):
             raise TypeError(
-                "DocumentLanguageClassifier expects a list of documents as input. "
-                "In case you want to classify a text, please use the TextLanguageClassifier."
+                "TransformerZeroShotDocumentClassifier expects a list of documents as input. "
+                "In case you want to classify and route a text, please use the TransformersZeroShotTextRouter."
             )
 
         invalid_doc_ids = []

releasenotes/notes/fix-classifiers-docstrings-messages-dcae473d2bd3cb95.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fix error messages for Document Classifier components, that suggested using nonexistent components for text
+    classification.