Entering /help /exit from within jshell gives the
following:

|
| /exit
|
| Leave the jshell tool. No work is saved.
| Save any work before using this command
|
| /exit
| Leave the jshell tool. The exit status is zero.
|
| /exit <integer-expression-snippet>
| Evaluate the snippet. If the snippet fails or is not an integer
expression,
| display the error. Otherwise leave the jshell tool with the
| value of the expression as the exit status

It looks like there are two different descriptions for /exit with no
argument, which is confusing. Formatting needs to be cleaned up to make it clear what happens with and without an argument.