[PATCH 2 of 6 v3] hghave: add docstring for check

[timeless]

# HG changeset patch
# User timeless <timeless at mozdev.org>
# Date 1459736256 0
#      Mon Apr 04 02:17:36 2016 +0000
# Node ID 458b58dfd3ff86e2c27beb852b529b249fb6a467
# Parent  4c33ba40ce7602e76f85e069ec8eb999a10871ed
hghave: add docstring for check

diff --git a/tests/hghave.py b/tests/hghave.py
--- a/tests/hghave.py
+++ b/tests/hghave.py
@@ -17,6 +17,7 @@
 }
 
 def check(name, desc):
+    """Registers a check function for a feature."""
     def decorator(func):
         checks[name] = (func, desc)
         return func