Intersphinx - incorrect links to pages containing spaces in their name

[alexandremoyer]

Describe the bug
Links that point to a file with spaces in its name and created through Intersphinx are incorrect.

To Reproduce

• Create a project "Example Project" with a file called File With Spaces.rst
• add a label test just before a chapter Test Chapter
• Configure another project that will use the Intersphinx extension pointing to Example Project (example).
• call a reference to the test label :ref:example:test.
• resulting link is pointing to File with displayed name With Spaces.html#$ Test Chapter

Here is the content the objects.inv

$ python -msphinx.ext.intersphinx buildExample\html\objects.inv
std:doc
        File With Spaces                         With Spaces.html Main chapter           : File
        index                                    Welcome to Example’s documentation!     : index.html
std:label
        file-with-space                          With Spaces.html#$ Main chapter         : File
        genindex                                 Index                                   : genindex.html
        modindex                                 Module Index                            : py-modindex.html
        py-modindex                              Python Module Index                     : py-modindex.html
        search                                   Search Page                             : search.html
        test                                     With Spaces.html#$ Test Chapter         : File

Expected behavior
Correct link should be Test Chapter and pointing to File With Spaces.html#test

Environment info

• Windows 10
• Python version: 3.7.3
• Sphinx version: 3.0.3
• Sphinx extensions: [sphinx.ext.intersphinx]