The error messages that result from inadvertantly erasing a } bracket are so obscure they often do not lead to the problem.
How about adding a simple bracket counter so if there are a different number of left brackets than right brackets it tells you to look for that. This would sure help us beginners.
You need to click next to a bracket and then the matching one of the pair is highlighted.
Another help for bigger sketches is to use the free editor "Notepad++" and set the language to C++. Then it highlights all the bracket pairs including embedded ones. See:
Tools + Auto Format WILL tell you that you have the wrong number of right or left braces, or will line things up neatly, though not necessarily correctly, if you have the same number of each.