Alcohol for drinking is ethanol... containing two of the hydrogen groups compared to one group in methanol. Sloppily made drinking alcohol can contain methanol, which happened a lot during the Prohibition and was a factor in repealing the law, because so many people were being poisoned. Legal taxed liquor is tightly regulated and inspected to insure adequate distillation, so don't worry.

You can get formaldehyde from many sources, one modern source is carpets and manufactured building materials. No doubt a cumulative effect occurs to people exposed to several different sources. For example, someone who smokes cigarettes, lives in a mobile home, drinks Aspartame® sweetened soda and works in a mortuary would probably get formaldehyde poisoning pretty quick.