I have tried to create a shortcut for accented characters: á, é, í, ó, ú, in order to be replaced in the source code by: \'a, \'e, \'i, \'o, \'u, for this I have modified the autocompletion.plist file by adding the lines
But the result is a little strange: ´\'a, ´\'e, ´\'i, ´\'o, ´\'u.
Is it possible to correct this?

inputencwith the UTF-8 encoding (with pdfLaTeX) or use XeLaTeX or LuaLaTeX and just enter them directly into your source. (Make sure you change the default encoding in TeXShop to UTF-8.) – Alan Munn Jun 11 '17 at 14:05