Make imports look like includes

Imports work like includes so they should use the relevant group-name.

I also renamed pythonPreCondit to pythonImport since it's specific to
that type of "preprocessor" statement.

syntax/python.vim

 syn keyword pythonStatement     def class nextgroup=pythonFunction skipwhite
 syn keyword pythonRepeat        for while
 syn keyword pythonConditional   if elif else
-syn keyword pythonPreCondit     import from
+syn keyword pythonImport        import from
 syn keyword pythonException     try except finally
 syn keyword pythonOperator      and in is not or
 
   if !s:Enabled("g:python_print_as_function")
     syn keyword pythonStatement  print
   endif
-  syn keyword pythonPreCondit   as
+  syn keyword pythonImport      as
   syn match   pythonFunction    "[a-zA-Z_][a-zA-Z0-9_]*" display contained
 else
   syn keyword pythonStatement   as nonlocal None
   endif
 
   HiLink pythonStatement        Statement
-  HiLink pythonPreCondit        Statement
+  HiLink pythonImport           Include
   HiLink pythonFunction         Function
   HiLink pythonConditional      Conditional
   HiLink pythonRepeat           Repeat