[MRG] scikit-learn#8218: in FAQ, link deep learning question to GPU question (scikit-learn#8220)

* linked deep learning question to gpu question.

* fix wording.

Author: vincentpham1991

doc/faq.rst

@@ -282,6 +282,9 @@ the design constraints of scikit-learn; as a result, deep learning
 and reinforcement learning are currently out of scope for what
 scikit-learn seeks to achieve.
 
+You can find more information about addition of gpu support at
+`Will you add GPU support?`_.
+
 Why is my pull request not getting any attention?
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