Improve redecoration error naming

[OrkhanAlikhanov]

Recently we got an error in a webpack production build.

ERROR in dashboard.2bbdd6.js from Terser
module redeclared [dashboard.2bbdd6.js:6659,6]

It was confusing for us what module it is that's being referred. It turned out it's not an actual module, it is a variable named module. Would be easy for us if it was saying "module" is redeclared or something named "module" is redeclared at:

terser/lib/scope.js

Line 321 in a0a50ea

node.name + " redeclared",

I know it throws with filename and the line number, but in our case it was a single huge bundled file

[fabiosantoscode]

Thanks for pointing this out? Want to send a PR? "module" is redeclared sounds great to me.

[OrkhanAlikhanov]

Is it okay to use ES6 template strings?

`"${node.name}" is redeclared`

[fabiosantoscode]

Yes, it is :)

[OrkhanAlikhanov]

Sent the PR #516