Of these, only <tab> completion is documented --

jshell> /help shortcuts
|
| shortcuts
|
| Supported shortcuts include:
|
| <tab>
| After entering the first few letters of a Java identifier,
| a jshell command, or, in some cases, a jshell command argument,
| press the <tab> key to complete the input.
| If there is more than one completion, then possible completions will be shown.
| Will show documentation if available and appropriate.
|
| Shift-<tab> v
| After a complete expression, hold down <shift> while pressing <tab>,
| then release and press "v", the expression will be converted to
| a variable declaration whose type is based on the type of the expression.
|
| Shift-<tab> m
| After a complete expression or statement, hold down <shift> while pressing <tab>,
| then release and press "m", the expression or statement will be converted to
| a method declaration. If an expression, the return type is based on the type
| of the expression.
|
| Shift-<tab> i
| After an unresolvable identifier, hold down <shift> while pressing <tab>,
| then release and press "i", and jshell will propose possible imports
| which will resolve the identifier based on the content of the specified classpath.


Note: Shift-<tab> m -- was added in JDK 10.