use shared-bindings struct doc; remove docs/library one

docs/library/index.rst

@@ -46,7 +46,6 @@ Not all of these are enabled on all WiFi-capable ports.
    collections.rst
    gc.rst
    hashlib.rst
-   struct.rst
    sys.rst
    uerrno.rst
    uio.rst

docs/library/struct.rst

@@ -1,44 +0,0 @@
-:mod:`struct` -- pack and unpack primitive data types
-======================================================
-
-.. include:: ../templates/unsupported_in_circuitpython.inc
-
-.. module:: struct
-   :synopsis: pack and unpack primitive data types
-
-|see_cpython_module| :mod:`cpython:struct`.
-
-Supported size/byte order prefixes: ``@``, ``<``, ``>``, ``!``.
-
-Supported format codes: ``b``, ``B``, ``h``, ``H``, ``i``, ``I``, ``l``,
-``L``, ``q``, ``Q``, ``s``, ``P``, ``f``, ``d`` (the latter 2 depending
-on the floating-point support).
-
-Functions
----------
-
-.. function:: calcsize(fmt)
-
-   Return the number of bytes needed to store the given *fmt*.
-
-.. function:: pack(fmt, v1, v2, ...)
-
-   Pack the values *v1*, *v2*, ... according to the format string *fmt*.
-   The return value is a bytes object encoding the values.
-
-.. function:: pack_into(fmt, buffer, offset, v1, v2, ...)
-
-   Pack the values *v1*, *v2*, ... according to the format string *fmt*
-   into a *buffer* starting at *offset*. *offset* may be negative to count
-   from the end of *buffer*.
-
-.. function:: unpack(fmt, data)
-
-   Unpack from the *data* according to the format string *fmt*.
-   The return value is a tuple of the unpacked values.
-
-.. function:: unpack_from(fmt, data, offset=0)
-
-   Unpack from the *data* starting at *offset* according to the format string
-   *fmt*. *offset* may be negative to count from the end of *buffer*. The return
-   value is a tuple of the unpacked values.