regex: Simplify code
regex: Simplify code

These conditionals can only be true if we set [se]blank above,
so we can move them inside the block.

thestinger/vte-ng,thestinger/vte-ng,thestinger/vte-ng,saitoha/vte-sixel,saitoha/vte-sixel,saitoha/vte-sixel