convert part of md to rst

docs/classes.rst

@@ -7,29 +7,33 @@ Lark
 .. autoclass:: lark.Lark
     :members: open, parse, save, load
 
-**Using Unicode character classes with regex**
 
-Python's builtin `re` module has a few persistent known bugs and also won't parse
-advanced regex features such as character classes.
-With `pip install lark-parser[regex]`, the `regex` module will be installed alongside `lark` and can act as a drop-in replacement to `re`.
+Using Unicode character classes with ``regex``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Any instance of `Lark` instantiated with `regex=True` will now use the `regex` module instead of `re`.
+Python’s builtin ``re`` module has a few persistent known bugs and also
+won’t parse advanced regex features such as character classes. With
+``pip install lark-parser[regex]``, the ``regex`` module will be
+installed alongside ``lark`` and can act as a drop-in replacement to
+``re``.
 
-For example, we can now use character classes to match PEP-3131 compliant Python identifiers.
+Any instance of ``Lark`` instantiated with ``regex=True`` will now use
+the ``regex`` module instead of ``re``. For example, we can now use
+character classes to match PEP-3131 compliant Python identifiers.
 
-Example:
-    ::
+::
 
-        from lark import Lark
-        >>> g = Lark(r"""
-                            ?start: NAME
-                            NAME: ID_START ID_CONTINUE*
-                            ID_START: /[\p{Lu}\p{Ll}\p{Lt}\p{Lm}\p{Lo}\p{Nl}_]+/
-                            ID_CONTINUE: ID_START | /[\p{Mn}\p{Mc}\p{Nd}\p{Pc}·]+/
-                        """, regex=True)
+    from lark import Lark
+    >>> g = Lark(r"""
+                        ?start: NAME
+                        NAME: ID_START ID_CONTINUE*
+                        ID_START: /[\p{Lu}\p{Ll}\p{Lt}\p{Lm}\p{Lo}\p{Nl}_]+/
+                        ID_CONTINUE: ID_START | /[\p{Mn}\p{Mc}\p{Nd}\p{Pc}·]+/
+                    """, regex=True)
+
+    >>> g.parse('வணக்கம்')
+    'வணக்கம்'
 
-        >>> g.parse('வணக்கம்')
-        'வணக்கம்'
 
 Tree
 ----
@@ -44,7 +48,7 @@ Token
 .. autoclass:: lark.Token
 
 Transformer, Visitor & Interpreter
----------------------------------
+----------------------------------
 
 See :doc:`visitors`.