shorten prearrow

IPython/frontend/html/notebook/static/css/tooltip.css

@@ -108,7 +108,7 b''
 }
 .pretooltiparrow {
   left: 0px;
-  margin-left: -25px;
+  margin-left: 0px;
   top: -16px;
   width: 70px;
   height: 16px;
@@ -118,10 +118,10 b''
 .pretooltiparrow:before {
   background-color: #f7f7f7;
   border: thin silver solid ;
-  z-index: 10;
+  z-index: 11;
   content: "";
   position: absolute;
-  left: 40px;
+  left: 15px;
   top: 10px;
   width: 25px;
   height: 25px;

IPython/frontend/html/notebook/static/less/tooltip.less

@@ -141,7 +141,7 b''
 
 .pretooltiparrow {
   left: 0px;
-  margin-left: -25px;
+  margin-left: 0px;
   top: -16px;
   width: 70px;
   height: 16px;
@@ -152,10 +152,10 b''
 .pretooltiparrow:before {
   background-color : @c4;
   border : thin silver solid ; 
-  z-index:10;
+  z-index:11;
   content: "";
   position: absolute;
-  left: 40px;
+  left: 15px;
   top: 10px;
   width: 25px;
   height: 25px;