(find-definition-noselect): Fix typo in the doc string:

"functoin" => "function".

lisp/ldefs-boot.el

@@ -10285,7 +10285,7 @@ See `find-variable' for more details.
 (autoload (quote find-definition-noselect) "find-func" "\
 Return a pair `(BUFFER . POINT)' pointing to the definition of SYMBOL.
 TYPE says what type of definition: nil for a function,
-`defvar' or `defface' for a variable or face.  This functoin
+`defvar' or `defface' for a variable or face.  This function
 does not switch to the buffer or display it.
 The library where SYMBOL is defined is searched for in FILE or