add a doc link for arrow.format (#1180)

Author: saranti

arrow/arrow.py

@@ -1088,7 +1088,8 @@ def format(
         self, fmt: str = "YYYY-MM-DD HH:mm:ssZZ", locale: str = DEFAULT_LOCALE
     ) -> str:
         """Returns a string representation of the :class:`Arrow <arrow.arrow.Arrow>` object,
-        formatted according to the provided format string.
+        formatted according to the provided format string. For a list of formatting values,
+        see :ref:`supported-tokens`
 
         :param fmt: the format string.
         :param locale: the locale to format.

docs/guide.rst

@@ -156,6 +156,8 @@ Move between the earlier and later moments of an ambiguous time:
 Format
 ~~~~~~
 
+For a list of formatting values, see :ref:`supported-tokens`
+
 .. code-block:: python
 
     >>> arrow.utcnow().format('YYYY-MM-DD HH:mm:ss ZZ')
@@ -365,6 +367,8 @@ Then get and use a factory for it:
     >>> custom.days_till_xmas()
     >>> 211
 
+.. _supported-tokens:
+
 Supported Tokens
 ~~~~~~~~~~~~~~~~