docs: fix ManagementStyle book name

Just corrected the book name. I'm probably the only one who ever read
this file :-)

Signed-off-by: Jiri Pirko <[e-mail]>
Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/ManagementStyle

···
 budget of your group, you're almost certainly not a kernel manager. 
 These suggestions may or may not apply to you. 
 
-First off, I'd suggest buying "Seven Habits of Highly Successful
+First off, I'd suggest buying "Seven Habits of Highly Effective
 People", and NOT read it.  Burn it, it's a great symbolic gesture. 
 
 (*) This document does so not so much by answering the question, but by