[3.14] gh-135447: Document the NOT_TAKEN & POP_ITER bytecode instructions (GH-135803) (#139399)

Co-authored-by: Yongzi Li <204532581+Yzi-Li@users.noreply.github.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
Co-authored-by: Ken Jin <kenjin4096@gmail.com>

Author: 4 people

Doc/library/dis.rst

@@ -585,6 +585,22 @@ operations on it as if it was a Python list. The top of the stack corresponds to
    generate line tracing events.
 
 
+.. opcode:: NOT_TAKEN
+
+   Do nothing code.
+   Used by the interpreter to record :monitoring-event:`BRANCH_LEFT`
+   and :monitoring-event:`BRANCH_RIGHT` events for :mod:`sys.monitoring`.
+
+   .. versionadded:: 3.14
+
+
+.. opcode:: POP_ITER
+
+   Removes the iterator from the top of the stack.
+
+   .. versionadded:: 3.14
+
+
 .. opcode:: POP_TOP
 
    Removes the top-of-stack item::