Trim filenames created via the fs_menu

The default when naming a file in the command line is that extra white
space will be stripped away. It seems logical for file naming via the
fs_menu in nerdtree to follow that convention.

I have left the defaults of `trim` because they seem sensible.

CHANGELOG.md

@@ -5,6 +5,7 @@
         - **.PATCH**: Pull Request Title (PR Author) [PR Number](Link to PR)
 -->
 #### 6.10
+- **.10**: Trim filenames created via the fs_menu (elanorigby) [#1238](https://github.com/preservim/nerdtree/pull/1238)
 - **.9**: `go` on a bookmark directory will NERDTreeFind it. (PhilRunninger) [#1236](https://github.com/preservim/nerdtree/pull/1236)
 - **.8**: Put `Callback` function variables in local scope. (PhilRunninger) [#1230](https://github.com/preservim/nerdtree/pull/1230)
 - **.7**: Fix mouse-clicking a file to open it. (PhilRunninger) [#1225](https://github.com/preservim/nerdtree/pull/1225)

nerdtree_plugin/fs_menu.vim

@@ -169,7 +169,7 @@ endfunction
 function! NERDTreeAddNode()
     let curDirNode = g:NERDTreeDirNode.GetSelected()
     let prompt = s:inputPrompt('add')
-    let newNodeName = input(prompt, curDirNode.path.str() . nerdtree#slash(), 'file')
+    let newNodeName = trim(input(prompt, curDirNode.path.str() . nerdtree#slash(), 'file'))
 
     if newNodeName ==# ''
         call nerdtree#echo('Node Creation Aborted.')
@@ -206,7 +206,7 @@ function! NERDTreeMoveNode()
     let newNodePath = input(prompt, curNode.path.str(), 'file')
     while filereadable(newNodePath)
         call nerdtree#echoWarning('This destination already exists. Try again.')
-        let newNodePath = input(prompt, curNode.path.str(), 'file')
+        let newNodePath = trim(input(prompt, curNode.path.str(), 'file'))
     endwhile
 
 
@@ -337,7 +337,7 @@ endfunction
 function! NERDTreeCopyNode()
     let currentNode = g:NERDTreeFileNode.GetSelected()
     let prompt = s:inputPrompt('copy')
-    let newNodePath = input(prompt, currentNode.path.str(), 'file')
+    let newNodePath = trim(input(prompt, currentNode.path.str(), 'file'))
 
     if newNodePath !=# ''
         "strip trailing slash