This patch fixes the spelling of "function" in the root source code
and documentation, which is misspelled (sometimes as part of larger
"function"-based words) at least 152 times:

* "funciton" 48 times
* "funcion" 36 times
* "funtion" 23 times
* "fucntion" 17 times
* "functionn" 6 times
* "fuction" 6 times
* "fuunction" 4 times
* "functioin" 3 times
* "fonction" 3 times
* "funstion" twice
* "fnuction" once
* "functiom" once
* "functio" once
* "funcition" once


git-svn-id: http://root.cern.ch/svn/root/trunk@30749 27541ba8-7e3a-0410-8455-c3a389f83636