4745 fix AVL code misspellings

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Robert Mustacchi <rm@joyent.com>

usr/src/common/avl/avl.c

@@ -37,15 +37,15 @@
  * insertion and deletion relatively efficiently. Searching the tree is
  * still a fast operation, roughly O(log(N)).
  *
- * The key to insertion and deletion is a set of tree maniuplations called
+ * The key to insertion and deletion is a set of tree manipulations called
  * rotations, which bring unbalanced subtrees back into the semi-balanced state.
  *
  * This implementation of AVL trees has the following peculiarities:
  *
  *	- The AVL specific data structures are physically embedded as fields
  *	  in the "using" data structures.  To maintain generality the code
  *	  must constantly translate between "avl_node_t *" and containing
- *	  data structure "void *"s by adding/subracting the avl_offset.
+ *	  data structure "void *"s by adding/subtracting the avl_offset.
  *
  *	- Since the AVL data is always embedded in other structures, there is
  *	  no locking or memory allocation in the AVL routines. This must be
@@ -94,7 +94,7 @@
 #include <sys/cmn_err.h>
 
 /*
- * Small arrays to translate between balance (or diff) values and child indeces.
+ * Small arrays to translate between balance (or diff) values and child indices.
  *
  * Code that deals with binary tree data structures will randomly use
  * left and right children when examining a tree.  C "if()" statements
@@ -114,7 +114,8 @@ static const int  avl_balance2child[]	= {0, 0, 1};
  *
  * - If there is a left child, go to it, then to it's rightmost descendant.
  *
- * - otherwise we return thru parent nodes until we've come from a right child.
+ * - otherwise we return through parent nodes until we've come from a right
+ *   child.
  *
  * Return Value:
  * NULL - if at the end of the nodes
@@ -919,7 +920,7 @@ avl_is_empty(avl_tree_t *tree)
 
 /*
  * Post-order tree walk used to visit all tree nodes and destroy the tree
- * in post order. This is used for destroying a tree w/o paying any cost
+ * in post order. This is used for destroying a tree without paying any cost
  * for rebalancing it.
  *
  * example:

usr/src/uts/common/sys/avl.h

@@ -39,7 +39,7 @@ extern "C" {
 #include <sys/avl_impl.h>
 
 /*
- * This is a generic implemenatation of AVL trees for use in the Solaris kernel.
+ * This is a generic implementation of AVL trees for use in the Solaris kernel.
  * The interfaces provide an efficient way of implementing an ordered set of
  * data structures.
  *
@@ -175,7 +175,7 @@ extern void avl_insert(avl_tree_t *tree, void *node, avl_index_t where);
  * Insert "new_data" in "tree" in the given "direction" either after
  * or before the data "here".
  *
- * This might be usefull for avl clients caching recently accessed
+ * This might be useful for avl clients caching recently accessed
  * data to avoid doing avl_find() again for insertion.
  *
  * new_data	- new data to insert