Fix several C-API doc typos caught by tomo cocoa on docs@.

The signature and description of PyException_SetCause now use "cause"
rather than "ctx" to match the code.
diff --git a/Doc/c-api/exceptions.rst b/Doc/c-api/exceptions.rst
index c3d978f..0aa892d 100644
--- a/Doc/c-api/exceptions.rst
+++ b/Doc/c-api/exceptions.rst
@@ -306,7 +306,7 @@
 
 .. c:function:: void PyErr_SyntaxLocation(char *filename, int lineno)
 
-   Like :c:func:`PyErr_SyntaxLocationExc`, but the col_offset parameter is
+   Like :c:func:`PyErr_SyntaxLocationEx`, but the col_offset parameter is
    omitted.
 
 
@@ -490,11 +490,11 @@
    reference, as accessible from Python through :attr:`__cause__`.
 
 
-.. c:function:: void PyException_SetCause(PyObject *ex, PyObject *ctx)
+.. c:function:: void PyException_SetCause(PyObject *ex, PyObject *cause)
 
-   Set the cause associated with the exception to *ctx*.  Use *NULL* to clear
-   it.  There is no type check to make sure that *ctx* is either an exception
-   instance or :const:`None`.  This steals a reference to *ctx*.
+   Set the cause associated with the exception to *cause*.  Use *NULL* to clear
+   it.  There is no type check to make sure that *cause* is either an exception
+   instance or :const:`None`.  This steals a reference to *cause*.
 
    :attr:`__suppress_context__` is implicitly set to ``True`` by this function.