Bug fixes in the RST

Author: TobiasWrigstad

peps/pep-0795.rst

@@ -903,7 +903,7 @@ itself during initialisation.
 
 
 Accessing subclass information and subclassing immutable classes
-================================================================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 When a class object becomes immutable, its base classes
 replace their interpreter-local registry of mutable
@@ -1201,7 +1201,7 @@ immutable, code must explicitly make it so, through a ``@frozen``
 decorator at definition-time, or through an explicit call to ``freeze()``
 on the type object itself. By using ``@freezable`` a declaration opts
 in to being frozen as a side-effect of freezing an instance.
-(A call to `set_freezable(cls, Yes)` has the same effect). 
+(A call to ``set_freezable(cls, Yes)`` has the same effect).
 This serves as documentation similar to the ``const`` propagation
 above, even though -- as Python is a dynamically checked language --
 this ``const``-like propagation will be driven by run-time errors