fix the kwargs typo, and a ref from plt to ax (#44)

Ch02-statlearn-lab.Rmd

@@ -655,7 +655,7 @@ ax.contour(x, y, f, levels=45);
 ```
 To fine-tune the output of the
 `ax.contour()`  function, take a
-look at the help file by typing `?plt.contour`.
+look at the help file by typing `ax.contour?`.
  
 The `ax.imshow()`  method is similar to 
 `ax.contour()`, except that it produces a color-coded plot

Ch03-linreg-lab.Rmd

@@ -300,7 +300,7 @@ def abline(ax, b, m, *args, **kwargs):
 
 ```
 The addition of `*args` allows any number of
-non-named arguments to `abline`, while `*kwargs` allows any
+non-named arguments to `abline`, while `**kwargs` allows any
 number of named arguments (such as `linewidth=3`) to `abline`.
 In our function, we pass
 these arguments verbatim to `ax.plot` above. Readers