Update treestyletab.dtd

Add some french translations
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More french translations

It was some remaining non translated texts.
I hope this is complete now.
Use ES6 Rest parameters.
Remove needless access to 'arguments'.
Fix breakage of hooked tabModule.Scriptish_openInTab
Fix breakage of *Now APIs
Call original "stop" method with all given arguments correctly
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Show the tab bar again correctly when I click the grippy in the splitter (#593)