Merge pull request mantidproject#20896 from mantidproject/fix_pdgui_r…

…elease

Fix file downloading issue with HFIR PD GUI

Add release notes

Merge pull request mantidproject#19826 from mantidproject/multi_file_…

…prop_cache

Add caching to multiple file property

added to release notes index

Release version 3.9.1

Merge pull request mantidproject#18798 from mantidproject/Fix_crash_o…

…n_release_3.9

Fix a crash when right-clicking on workspace information

Merge pull request mantidproject#17749 from mantidproject/17748_rever…

…t_mantid_dock_fix

Bring back old delete behaviour for Mantid Dock

Releasing v3.7.2