patch 8.0.0916: cannot specify properties of window for terminal open

Problem:    Cannot specify properties of window for when opening a window for
            a finished terminal job.
Solution:   Add "term_opencmd".
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index bd92b3d..bf8bae4 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -8085,6 +8085,12 @@
 					"open": open window if needed
 				     Note that "open" can be interruptive.
 				     See |term++close| and |term++open|.
+		   "term_opencmd"    command to use for opening the window when
+				     "open" is used for "term_finish"; must
+				     have "%d" where the buffer number goes,
+				     e.g. "10split|buffer %d"; when not
+				     specified "botright sbuf %d" is used
+
 		{only available when compiled with the |+terminal| feature}
 
 term_wait({buf} [, {time}])					*term_wait()*