Replace curly quotes with straight quotes

Curly quotes usually input from Chinese input method.
When read from english context, it makes some confusion.

Change-Id: I6209f92de2a5b136c2c16decfe5752f5c44096ff
diff --git a/HACKING.rst b/HACKING.rst
index a3e9c26..f961884 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -385,7 +385,7 @@
 
 Otherwise the bug fix won't be able to land in the project.
 
-Handily, `Zuul’s cross-repository dependencies
+Handily, `Zuul's cross-repository dependencies
 <https://docs.openstack.org/infra/zuul/user/gating.html#cross-project-dependencies>`_.
 can be leveraged to do without step 2 and to have steps 3 and 4 happen
 "atomically". To do that, make the patch written in step 1 to depend (refer to