micropython: Document heap_lock, heap_unlock.

Fixes #116

doc/main/micropython/micropython.rst

@@ -6,16 +6,20 @@
 
 .. autofunction:: micropython.const
 
-.. autofunction:: micropython.opt_level
+.. autofunction:: micropython.heap_lock
+
+.. autofunction:: micropython.heap_unlock
+
+.. autofunction:: micropython.kbd_intr
 
 .. autofunction:: micropython.mem_info
 
-.. autofunction:: micropython.qstr_info
+.. autofunction:: micropython.opt_level
 
+.. autofunction:: micropython.qstr_info
+
 .. autofunction:: micropython.stack_use
 
-.. autofunction:: micropython.kbd_intr
-
 
 Examples
 ---------------------

jedi/tests/test_complete_import.py

@@ -150,6 +150,8 @@ def test_from_micropython_import():
     assert [c["insertText"] for c in completions] == [
         "const",
         "kbd_intr",
+        "heap_lock",
+        "heap_unlock",
         "mem_info",
         "opt_level",
         "qstr_info",

src/micropython/__init__.py

@@ -108,7 +108,27 @@ def stack_use() -> int:
     """
 
 
-# REVISIT: Skipping heap lock funcs for now
+def heap_lock() -> None:
+    """
+    heap_lock()
+
+    Locks the heap. When locked, no memory allocation can occur. A
+    ``MemoryError`` will be raised if any heap allocation is attempted.
+    """
+
+
+def heap_unlock() -> int:
+    """
+    heap_unlock() -> int
+
+    Unlocks the heap. Memory allocation is now allowed again.
+
+    If :func:`heap_lock()` was called multiple times, :func:`heap_unlock()`
+    must be called the same number of times to make the heap available again.
+
+    Returns:
+        The lock depth after unlocking. It is ``0`` once it is unlocked.
+    """
 
 
 def kbd_intr(chr: int) -> None: