fix: remove defaults from sectioner args

`_split_elements_by_title_and_table()` is an implementation function
(private). It is called only by `chunk_by_title()` (outside tests) and
with all arguments specified, so has no need for defaults since they are
never used and complicate reasoning about its behavior.

Remove defaults from all parameters to
`_split_elements_by_title_and_table()`.

test_unstructured/chunking/test_title.py

@@ -149,7 +149,13 @@ def test_split_elements_by_title_and_table():
         Text("It is storming outside."),
         CheckBox(),
     ]
-    sections = _split_elements_by_title_and_table(elements, combine_text_under_n_chars=0)
+    sections = _split_elements_by_title_and_table(
+        elements,
+        multipage_sections=True,
+        combine_text_under_n_chars=0,
+        new_after_n_chars=500,
+        max_characters=500,
+    )
 
     assert sections == [
         [

unstructured/chunking/title.py

@@ -194,10 +194,10 @@ def chunk_by_title(
 
 def _split_elements_by_title_and_table(
     elements: List[Element],
-    multipage_sections: bool = True,
-    combine_text_under_n_chars: int = 500,
-    new_after_n_chars: int = 500,
-    max_characters: int = 500,
+    multipage_sections: bool,
+    combine_text_under_n_chars: int,
+    new_after_n_chars: int,
+    max_characters: int,
 ) -> List[List[Element]]:
     sections: List[List[Element]] = []
     section: List[Element] = []