[refactor] Add message to text_output click callback

Message from Picotron containing info about mouse position (mx and my
fields). It will be needed later to write custom callbacks reacting in a
different way based on the mouse position. For example, tree will use it
to check whether user clicked the "node collapse" button.

gui/gui.lua

@@ -81,7 +81,7 @@ local function start_test(item)
 				local text = printed_lines:line(selected_test_id, line_no)
 				return find_lua_file_in_text(text) != nil
 			end,
-			link_click = function(line_no)
+			link_click = function(line_no, msg)
 				local text = printed_lines:line(selected_test_id, line_no)
 
 				local file = find_lua_file_in_text(text)

gui/text_output.lua

@@ -36,7 +36,7 @@ function attach_text_output(parent, el)
 	function text_output:click(msg)
 		local line = line_at_mouse_position(msg)
 		if is_link(line) and el.link_click != nil then
-			el.link_click(line)
+			el.link_click(line, msg)
 		end
 	end
 

gui/tree.lua

@@ -43,7 +43,7 @@ function attach_tree(parent_el, el)
 		is_link = function(line_no)
 			return true
 		end,
-		link_click = function(line_no)
+		link_click = function(line_no, msg)
 			selected_line = line_no
 			el.select(provider:get_node(line_no).id)
 		end,