Editorial: fix the Unary - Operator's description

[fangniyima]

Closes #3024
change:
The unary - operator converts its operand to Number type and then negates it.
to:
The unary - operator converts its operand to a numeric value and then negates it.

[hax]

Maybe we could change "Number type" (6.1.6.1 The Number Type) to "Numeric type" (6.1.6 Numeric Types) ?

[jmdyck]

@hax:

Maybe we could change "Number type" (6.1.6.1 The Number Type) to "Numeric type" (6.1.6 Numeric Types) ?

I.e., you're suggesting "... converts its operand to Numeric type ..."?

I don't think that works, because it implies there's a type named "Numeric", which there isn't.