Autocomplete forces user to press enter twice to evaluate

[Former user]

When the end of an expression is a variable or unit (eg 'meter'), autocomplete forces the user to press enter twice to evaluate the expression. The first press completes the insertion of the variable (even if its already fully typed out), and the second evaluates the expression.

For example, typing out:

123 inch in meter

Would require two enter presses at the end to evaluate.

Either add option to disable enter for autocomplete purposes (ie tab only), or interpret an enter press as a request to evaluate when a variable or unit is already fully typed out.

[Helder Correia]

I guess we could stick to Tab exclusively for autocompletion and leave Enter for evaluation. BTW, through validation of this issue I found issue #750. @Teyut @polwel @fk @thadrien any thoughts?