template: uses <%_ to fix indent of node-gtk's index.d.ts
template: uses <%_ to fix indent of node-gtk's index.d.ts

Without <%_, the preceeding space won't be removed and will be included
in front of any following line. This has significance when outputing
`// <reference` line, as TS (at least in VSCode) won't read the line if
it's indented at all.

sammydre/ts-for-gjs,sammydre/ts-for-gjs