I have worked at a processing facility for three years as the head of the shipping department. Last week, when my time with the company came to a close, my supervisor wrote a letter of recommendation and asked me to refer any future employers to him. He assured me that he would give them glowing reviews, etc. I'm very appreciative of his kindness and his generosity, but there are three or four grammatical errors in the letter. Is it unethical to edit those errors? Would it be considered "edgy"? It's nothing but awkwardly placed commas and a single typo.
Speaking strictly as a matter of ethics, I would have to say no, it would not be unethical so long as you did not change any of the actual words (other than perhaps correcting their spelling) or change the meaning / intent of the letter. I would further add that you may even be saving the person some level of embarrassment.
I think you should not edit anything. Maybe you do a mistake and change the meaning (or just the font) or someone checks the creation date of the file and sees that it does not fit or something else. You'd submit a manipulated version of a recommendation even if you do it with a good intention. Rather ask your supervisor to correct it.