fix: Make NERDTreeFind to handle directory case sensitivity (#1387)

Co-authored-by: Dan Gibson <danial.gibson@spin.net.au>

lib/nerdtree/path.vim

@@ -549,7 +549,7 @@ function! s:Path.isUnder(parent)
         return 0
     endif
     for i in range(0, l:that_count-1)
-        if self.pathSegments[i] !=# a:parent.pathSegments[i]
+        if !nerdtree#pathEquals(self.pathSegments[i], a:parent.pathSegments[i])
             return 0
         endif
     endfor

lib/nerdtree/tree_dir_node.vim

@@ -121,9 +121,15 @@ function! s:TreeDirNode.findNode(path)
     if a:path.equals(self.path)
         return self
     endif
+    if nerdtree#caseSensitiveFS()
         if stridx(a:path.str(), self.path.str(), 0) ==# -1
             return {}
         endif
+    else
+        if stridx(tolower(a:path.str()), tolower(self.path.str()), 0) ==# -1
+            return {}
+        endif
+    endif
 
     if self.path.isDirectory
         for i in self.children