What are these two keys, ⇞ and ⇟? I see keyboard shortcuts in the menu of Brackets. There are two symbols that look like up arrow and down arrow, could anyone tell me what they are?
Those are the page-up ⇞ and page-down ⇟ keys (on keyboards without them, use fn-Cursor up/down). For a list of other common key symbols, see this answer.