checkdoc-autofix-flag is a variable defined in `checkdoc.el'.
Its value is

Non-nil means attempt auto-fixing of doc strings.
If this value is the symbol `query', then the user is queried before
any change is made. If the value is `automatic', then all changes are
made without asking unless the change is very-complex. If the value
is `semiautomatic' or any other value, then simple fixes are made
without asking, and complex changes are made by asking the user first.
The value `never' is the same as nil, never ask or change anything.

You can customize this variable.