Notepad++ v8.9.6 regression fixes, bug-fixes:

1. Fix x86 installer regression of not showing installation entry in “Unstall a program” of Control Panel. (Fix community discussion)
2. Fix x86 installer regression where context menu not installed or uninstalled correctly. (Fix community discussion)
3. Fix UAC prompt display regression (“Notepad++ installer” instead of “Notepad++”) for Notepad++ v8.9.5. (Fix GitHub comment)
4. Fix incorrect bevaviour when saving dirty read-only files. (Fix #17956)
5. Fix regression where saving a UDL file removed XML declaration. (Fix GitHub comment)