[tune] fix doc typo and also make sure to clean "/" from config (#1476)

doc/source/tune.rst

@@ -90,7 +90,7 @@ To use rllab's VisKit (you may have to install some dependencies), run:
 
 .. image:: ray-tune-viskit.png
 
-Finally, to view the results with a `parallel coordinates visualization <https://en.wikipedia.org/wiki/Parallel_coordinates>`__, open `ParalleCoordinatesVisualization.ipynb <https://github.com/ray-project/ray/blob/master/python/ray/tune/ParallelCoordinatesVisualization.ipynb>`__ as follows and run its cells:
+Finally, to view the results with a `parallel coordinates visualization <https://en.wikipedia.org/wiki/Parallel_coordinates>`__, open `ParallelCoordinatesVisualization.ipynb <https://github.com/ray-project/ray/blob/master/python/ray/tune/ParallelCoordinatesVisualization.ipynb>`__ as follows and run its cells:
 
 .. code-block:: bash
 
@@ -146,7 +146,7 @@ Note that some trial schedulers such as HyperBand require your Trainable to supp
       Bracket(n=34, r=3, completed=0%): {'RUNNING': 2, 'PENDING': 32}
       Bracket(n=81, r=1, completed=0%): {'PENDING': 38}
     Resources used: 4/4 CPUs, 0/0 GPUs
-    Result logdir: /home/eric/ray_results/hyperband_test
+    Result logdir: ~/ray_results/hyperband_test
     PAUSED trials:
      - my_class_0_height=99,width=43:	PAUSED [pid=11664], 0 s, 100 ts, 97.1 rew
      - my_class_11_height=85,width=81:	PAUSED [pid=11771], 0 s, 33 ts, 32.8 rew

python/ray/tune/variant_generator.py

@@ -128,7 +128,7 @@ def _format_vars(resolved_vars):
                 last_string = False
                 pieces.append(k)
         pieces.reverse()
-        out.append("_".join(pieces) + "=" + _clean_value(value))
+        out.append(_clean_value("_".join(pieces)) + "=" + _clean_value(value))
     return ",".join(out)
 
 
@@ -136,7 +136,7 @@ def _clean_value(value):
     if isinstance(value, float):
         return "{:.5}".format(value)
     else:
-        return str(value)
+        return str(value).replace("/", "_")
 
 
 def _generate_variants(spec):