fix(ui): don't pad empty lines (#768)

Author: lervag

lua/lazy/view/text.lua

@@ -72,6 +72,9 @@ function Text:render(buf)
       str = str .. segment.str
     end
 
+    if str:match("^%s*$") then
+      str = ""
+    end
     table.insert(lines, str)
   end