pep550: Move pics one level up to show up on Python.org (#332)

pep-0550.rst

@@ -233,7 +233,7 @@ For regular Python code, EC behaves just like a thread-local.  Any
 modification of the EC object produces a new one, which is immediately
 set as the current one for the thread state.
 
-.. figure:: pep-0550/functions.png
+.. figure:: pep-0550-functions.png
    :align: center
    :width: 90%
 
@@ -338,7 +338,7 @@ is needed:
 Figure 2 below illustrates how execution context mutations work with
 coroutines.
 
-.. figure:: pep-0550/coroutines.png
+.. figure:: pep-0550-coroutines.png
    :align: center
    :width: 90%
 
@@ -418,7 +418,7 @@ is never modified by the interpreter.  ``yield from o`` expression in
 regular generators that are not decorated with ``types.coroutine``,
 is semantically equivalent to ``for v in o: yield v``.
 
-.. figure:: pep-0550/generators.png
+.. figure:: pep-0550-generators.png
    :align: center
    :width: 90%
 
@@ -641,7 +641,7 @@ While working on the reference implementation of this PEP, we were
 able to optimize ``dict.copy()`` operation **5.5x**, see [4]_ for
 details.
 
-.. figure:: pep-0550/dict_copy.png
+.. figure:: pep-0550-dict_copy.png
    :align: center
    :width: 100%
 
@@ -708,7 +708,7 @@ be essentially O(1) for relatively small mappings in EC.
 To assess if HAMT can be used for Execution Context, we implemented
 it in CPython [7]_.
 
-.. figure:: pep-0550/hamt_vs_dict.png
+.. figure:: pep-0550-hamt_vs_dict.png
    :align: center
    :width: 100%
 
@@ -718,7 +718,7 @@ Figure 5 shows that HAMT indeed displays O(1) performance for all
 benchmarked dictionary sizes.  For dictionaries with less than 100
 items, HAMT is a bit slower than Python dict/shallow copy.
 
-.. figure:: pep-0550/lookup_hamt.png
+.. figure:: pep-0550-lookup_hamt.png
    :align: center
    :width: 100%