gh-151950: Fix dangling class reference in pickletools docs

Doc/library/pickletools.rst

@@ -108,7 +108,7 @@ Programmatic interface
 
    Provides an :term:`iterator` over all of the opcodes in a pickle, returning a
    sequence of ``(opcode, arg, pos)`` triples.  *opcode* is an instance of an
-   :class:`OpcodeInfo` class; *arg* is the decoded value, as a Python object, of
+   :class:`!OpcodeInfo` class; *arg* is the decoded value, as a Python object, of
    the opcode's argument; *pos* is the position at which this opcode is located.
    *pickle* can be a string or a file-like object.
 

Doc/tools/.nitignore

@@ -18,7 +18,6 @@ Doc/library/lzma.rst
 Doc/library/mmap.rst
 Doc/library/multiprocessing.rst
 Doc/library/optparse.rst
-Doc/library/pickletools.rst
 Doc/library/pyexpat.rst
 Doc/library/select.rst
 Doc/library/socket.rst