bpo-38407: Add docstrings for typing.SupportsXXX classes. (GH-16644)

Lib/typing.py

@@ -1513,6 +1513,7 @@ Type.__doc__ = \
 
 @runtime_checkable
 class SupportsInt(Protocol):
+    """An ABC with one abstract method __int__."""
     __slots__ = ()
 
     @abstractmethod
@@ -1522,6 +1523,7 @@ class SupportsInt(Protocol):
 
 @runtime_checkable
 class SupportsFloat(Protocol):
+    """An ABC with one abstract method __float__."""
     __slots__ = ()
 
     @abstractmethod
@@ -1531,6 +1533,7 @@ class SupportsFloat(Protocol):
 
 @runtime_checkable
 class SupportsComplex(Protocol):
+    """An ABC with one abstract method __complex__."""
     __slots__ = ()
 
     @abstractmethod
@@ -1540,6 +1543,7 @@ class SupportsComplex(Protocol):
 
 @runtime_checkable
 class SupportsBytes(Protocol):
+    """An ABC with one abstract method __bytes__."""
     __slots__ = ()
 
     @abstractmethod
@@ -1549,6 +1553,7 @@ class SupportsBytes(Protocol):
 
 @runtime_checkable
 class SupportsIndex(Protocol):
+    """An ABC with one abstract method __index__."""
     __slots__ = ()
 
     @abstractmethod
@@ -1558,6 +1563,7 @@ class SupportsIndex(Protocol):
 
 @runtime_checkable
 class SupportsAbs(Protocol[T_co]):
+    """An ABC with one abstract method __abs__ that is covariant in its return type."""
     __slots__ = ()
 
     @abstractmethod
@@ -1567,6 +1573,7 @@ class SupportsAbs(Protocol[T_co]):
 
 @runtime_checkable
 class SupportsRound(Protocol[T_co]):
+    """An ABC with one abstract method __round__ that is covariant in its return type."""
     __slots__ = ()
 
     @abstractmethod