update doc

doc/traqvim.jax

@@ -271,19 +271,31 @@ bellow.
 https://github.com/gw31415/denops-sixel-view.vim
 
 >
+	" Clear the image like <C-l>
+	function s:clear() abort
+		call sixel_view#clear()
+	endfunction
+
 	function s:preview_img(fileId) abort
-		let file = denops#request("traqvim", "getFile", [a:fileId])
-		call sixel_view#view_sixel(file['data'], 0, 0)
+		" download the file and convert it to sixel data
+		let sixel = denops#request("traqvim", "getFile", [a:fileId])
+		call sixel_view#view_sixel(sixel['data'], 0, 0)
 	endfunction
 
 	function s:preview_cursor_img() abort
 		let cursor_url = getline('.')
 		let fileId = matchstr(cursor_url, 'https://q.trap.jp/files/\zs.*')
 		call s:preview_img(fileId)
+		" Close the image by moving the cursor
+		autocmd CursorMoved,BufLeave <buffer> ++once call s:clear()
+	endfunction
+
+	function s:traqvim_setting()
+		nnoremap <buffer><silent> K
+					\ <Cmd>call <SID>preview_cursor_img()<CR>
 	endfunction
 
-	nnoremap <buffer><silent> K
-				\ <Cmd>call <SID>preview_cursor_img()<CR>
+	autocmd FileType traqvim call s:traqvim_setting()
 <
 
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