Fix two minor typos (#1108)

Author: fingolfin

src/execute_request.jl

@@ -1,4 +1,4 @@
-# Handers for execute_request and related messages, which are
+# Handlers for execute_request and related messages, which are
 # the core of the Jupyter protocol: execution of Julia code and
 # returning results.
 

src/inline.jl

@@ -102,7 +102,7 @@ function display(d::InlineDisplay, x)
 end
 
 # we overload redisplay(d, x) to add x to a queue of objects to display,
-# with the actual display occuring when display() is called or when
+# with the actual display occurring when display() is called or when
 # an input cell has finished executing.
 
 function redisplay(d::InlineDisplay, x)