Path name with spaces converted to "%20" by Jupyter Notebook was not valid for saving

[biallenchanuow]

Environment
Jupyter Notebook version: 6.0.1
Conda version: 4.8.2
Python version: 3.7.10
Platform: Mac OS version 10.15.3
Browser Version: Google Chrome - Version 90.0.4430.212 (Official Build) (x86_64)

Description
I have encountered this issue when I tried to save a Notebook file in the subpath of the current path which has spaces in its name - the spaces were automatically converted to "%20", but the file failed to be saved without any changes to the original pathname, except for adding a subpath at the end. Removing the "%20" markers and added the spaces back did work though.

Error.7_No_Such_File_Or_Directory_Error_When_Save_As_With_File_Path_Containing_.20.mov

[kevin-bates]

This should be resolved via #6030 and available in the 6.4.0 release.

[biallenchanuow]

Thank you @kevin-bates