RTL Improvements
RTL Improvements

Do not apply negative line separation to the last line.
Ensure all methods immediately update cache in a single thread mode.
Fix bbcode_enabled change not being applied until text is changed.
Fix crash if line height is zero or less.

guilhermefelipecgs/godot,vkbsb/godot,godotengine/godot,sanikoyes/godot,guilhermefelipecgs/godot,BastiaanOlij/godot,godotengine/godot,vkbsb/godot,godotengine/godot,josempans/godot,pkowal1982/godot,sanikoyes/godot,pkowal1982/godot,sanikoyes/godot,BastiaanOlij/godot,vkbsb/godot,sanikoyes/godot,guilhermefelipecgs/godot,josempans/godot,Shockblast/godot,sanikoyes/godot,pkowal1982/godot,guilhermefelipecgs/godot,Shockblast/godot,josempans/godot,vkbsb/godot,BastiaanOlij/godot,Shockblast/godot,Shockblast/godot,guilhermefelipecgs/godot,vkbsb/godot,guilhermefelipecgs/godot,godotengine/godot,BastiaanOlij/godot,Shockblast/godot,vkbsb/godot,pkowal1982/godot,pkowal1982/godot,Shockblast/godot,godotengine/godot,josempans/godot,sanikoyes/godot,sanikoyes/godot,vkbsb/godot,godotengine/godot,guilhermefelipecgs/godot,Shockblast/godot,josempans/godot,vkbsb/godot,sanikoyes/godot,godotengine/godot,josempans/godot,josempans/godot,BastiaanOlij/godot,guilhermefelipecgs/godot,Shockblast/godot,godotengine/godot,BastiaanOlij/godot,BastiaanOlij/godot,pkowal1982/godot,pkowal1982/godot,BastiaanOlij/godot,josempans/godot,pkowal1982/godot