Fix plural mistake in Set* docs (#154)

toml.go

@@ -171,14 +171,14 @@ func (t *TomlTree) GetDefault(key string, def interface{}) interface{} {
 
 // Set an element in the tree.
 // Key is a dot-separated path (e.g. a.b.c).
-// Creates all necessary intermediates trees, if needed.
+// Creates all necessary intermediate trees, if needed.
 func (t *TomlTree) Set(key string, value interface{}) {
 	t.SetPath(strings.Split(key, "."), value)
 }
 
 // SetPath sets an element in the tree.
 // Keys is an array of path elements (e.g. {"a","b","c"}).
-// Creates all necessary intermediates trees, if needed.
+// Creates all necessary intermediate trees, if needed.
 func (t *TomlTree) SetPath(keys []string, value interface{}) {
 	subtree := t
 	for _, intermediateKey := range keys[:len(keys)-1] {