Reformat the commentary in the TreeDirNode script

The commentary in "tree_dir_node.vim" needed to be cleaned up a
little. Spaces after leading quotes are a good idea, to avoid the
"clustered" appearance that comments can sometimes have.

Use the following substitution command...

  :s/^"\ze\S/" /

to make this change to longer scripts.

lib/nerdtree/tree_dir_node.vim

@@ -1,13 +1,17 @@
+" ============================================================================
 " CLASS: TreeDirNode
+"
 " A subclass of NERDTreeFileNode.
 "
 " The 'composite' part of the file/dir composite.
-"============================================================
+" ============================================================================
+
+
 let s:TreeDirNode = copy(g:NERDTreeFileNode)
 let g:NERDTreeDirNode = s:TreeDirNode
 
 " FUNCTION: TreeDirNode.AbsoluteTreeRoot(){{{1
-"class method that returns the highest cached ancestor of the current root
+" Class method that returns the highest cached ancestor of the current root.
 function! s:TreeDirNode.AbsoluteTreeRoot()
     let currentNode = b:NERDTree.root
     while currentNode.parent != {}
@@ -157,6 +161,7 @@ endfunction
 
 " FUNCTION: TreeDirNode.getChildByIndex(indx, visible) {{{1
 " returns the child at the given index
+"
 " Args:
 " indx: the index to get the child from
 " visible: 1 if only the visible children array should be used, 0 if all the
@@ -201,7 +206,8 @@ function! s:TreeDirNode.getChildIndex(path)
 endfunction
 
 " FUNCTION: TreeDirNode.getDirChildren() {{{1
-"Get all children that are directories
+" Return a list of all child nodes from "self.children" that are of type
+" TreeDirNode.
 function! s:TreeDirNode.getDirChildren()
     return filter(self.children, 'v:val.path.isDirectory == 1')
 endfunction
@@ -372,7 +378,7 @@ function! s:TreeDirNode._initChildren(silent)
 endfunction
 
 " FUNCTION: TreeDirNode.New(path, nerdtree) {{{1
-"Returns a new TreeNode object with the given path and parent
+" Return a new TreeDirNode object with the given path and parent.
 "
 " Args:
 " path: dir that the node represents
@@ -437,8 +443,8 @@ function! s:TreeDirNode.openAlong(...)
 endfunction
 
 " FUNCTION: TreeDirNode.openExplorer() {{{1
-" opens an explorer window for this node in the previous window (could be a
+" Open an explorer window for this node in the previous window. The explorer
-" nerd tree or a netrw)
+" can be a NERDTree window or a netrw window.
 function! s:TreeDirNode.openExplorer()
     call self.open({'where': 'p'})
 endfunction
@@ -572,13 +578,11 @@ function! s:TreeDirNode.reveal(path, ...)
 endfunction
 
 " FUNCTION: TreeDirNode.removeChild(treenode) {{{1
-"
+" Remove the given treenode from "self.children".
-"Removes the given treenode from this nodes set of children
+" Throws "NERDTree.ChildNotFoundError" if the node is not found.
 "
 " Args:
-"treenode: the node to remove
+" treenode: the node object to remove
-"
-"Throws a NERDTree.ChildNotFoundError if the given treenode is not found
 function! s:TreeDirNode.removeChild(treenode)
     for i in range(0, self.getChildCount()-1)
         if self.children[i].equals(a:treenode)
@@ -591,10 +595,7 @@ function! s:TreeDirNode.removeChild(treenode)
 endfunction
 
 " FUNCTION: TreeDirNode.sortChildren() {{{1
-"
+" Sort "self.children" by alphabetical order and directory priority.
-"Sorts the children of this node according to alphabetical order and the
-"directory priority.
-"
 function! s:TreeDirNode.sortChildren()
     let CompareFunc = function("nerdtree#compareNodesBySortKey")
     call sort(self.children, CompareFunc)