pluma 1.23.3 release

Changes since the last release: v1.23.2...v1.23.3

pluma 1.23.3

• Translations update
• Update copyright to 2020
• avoid to make new Gsettings variables
• use Gsettings 'pluma_prefs_manager' instead
• Taglist: Load the local translation string from lang.mo file
• ignore comment element in xml file
• add translator hints
• migrate from intltool to gettext
• sync with fixed uk translations uk from transifex
• window: Do not override GdkWindowState
• pluma-document: avoid garbarge value in 'file_with_bom' function
• preferences: Change Draw to Show
• document-loader: remove unused variables
• smart-converter: Fix memory leaks