fix some small signal error

100 Numpy exercises with hint.ipynb

@@ -17,7 +17,7 @@
    "metadata": {},
    "source": [
     "#### 1. Import the numpy package under the name `np` (★☆☆) \n",
-    "(**hint**: import ... as ..)"
+    "(**hint**: import … as …)"
    ]
   },
   {

100 Numpy exercises with hint.md

@@ -12,7 +12,7 @@ free to open an issue at <https://github.com/rougier/numpy-100>
 
 #### 1. Import the numpy package under the name `np` (★☆☆) 
 
-(**hint**: import … as ..)
+(**hint**: import … as …)