refactor: rename test_data to _test_data and update related variables for clarity

Author: thorwhalen

tabled/tests/util.py

@@ -12,12 +12,12 @@ def local_text(*path):
     return local_posix(*path).read_text()
 
 
-test_data_path = ("tests", "data")
-test_data_posix = local_posix(*test_data_path)
+_test_data_path = ("tests", "data")
+_test_data_posix = local_posix(*_test_data_path)
 
 
-def test_data(name, text=False):
-    name_posix = test_data_posix.joinpath(name)
+def _test_data(name, text=False):
+    name_posix = _test_data_posix.joinpath(name)
     if not text:
         return name_posix.read_bytes()
     else: