Fix poor comments

Python/025_tryexcept.py

@@ -28,8 +28,6 @@ while age < 0:
 # Print a blank line
 print()
 
-# Calculate 
-
 # Show the user what they typed
 # the "f" before the quote means that this string is "formatted"
 # Formatted strings can use curly bracket notation to embed

Python/030_uselibrary.py

@@ -1,4 +1,4 @@
-# Basic example of using try/except to catch errors
+# Basic example of importing a library/module/class
 
 # import the datetime library
 # This imports the "datatime" class from the "datetime" module