Update Standard Library sys documentation

docs/library/sys.rst

@@ -15,6 +15,21 @@ Functions
    function raise as `SystemExit` exception. If an argument is given, its
    value given as an argument to `SystemExit`.
 
+.. function:: print_exception(exc, file=sys.stdout, /)
+
+   Print exception with a traceback to a file-like object *file* (or
+   `sys.stdout` by default).
+
+   .. admonition:: Difference to CPython
+      :class: attention
+
+      This is simplified version of a function which appears in the
+      ``traceback`` module in CPython. Unlike ``traceback.print_exception()``,
+      this function takes just exception value instead of exception type,
+      exception value, and traceback object; *file* argument should be
+      positional; further arguments are not supported. CPython-compatible
+      ``traceback`` module can be found in `micropython-lib`.
+
 Constants
 ---------
 
@@ -97,12 +112,6 @@ Constants
    If you need to check whether your program runs on CircuitPython (vs other
    Python implementation), use `sys.implementation` instead.
 
-.. data:: ps1
-          ps2
-
-   Mutable attributes holding strings, which are used for the REPL prompt.  The defaults
-   give the standard Python prompt of ``>>>`` and ``...``.
-
 .. data:: stderr
 
    Standard error ``stream``.
@@ -115,14 +124,6 @@ Constants
 
    Standard output ``stream``.
 
-.. data:: tracebacklimit
-
-   A mutable attribute holding an integer value which is the maximum number of traceback
-   entries to store in an exception.  Set to 0 to disable adding tracebacks.  Defaults
-   to 1000.
-
-   Note: this is not available on all ports.
-
 .. data:: version
 
    Python language version that this implementation conforms to, as a string.