docs: add truncate helper

Author: Aidenable

docs/source/utils/index.rst

@@ -7,3 +7,4 @@ Utils
     suppress_not_modified
     logging
     retry
+    truncate

docs/source/utils/truncate.rst

@@ -0,0 +1,10 @@
+✂️ truncate
+=============================
+
+Truncates a string to a given length.
+
+.. code-block:: python
+
+   from raito.utils.helpers.truncate import truncate
+
+   truncate("Hello, world!", 8)  # Returns "Hello..."