fixed PY-14360Shift+enter stopped to work in "Run manage.py task..." dialog

there is no need to register shift+enter in plugin.xml for ipnb, we already registered it as custom shortcut on code source panel
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
IDEA-117343 When plugin can't be loaded (i.e. due to IDEA upgrade), related IDE settings are lost
avoid calling VirtualFile.getFileType in fileCreated because it can start detecting binary or particular type from content (IDEA-133507)
custom thread pool executor for icon calculation
(if needed) add EAP suffix for updated version (IDEA-133731)
Cleanup (less specialized type)
Cleanup (formatting; dead code)
Merge remote-tracking branch 'origin/master'
Cleanup (javadoc updated)