vteseq: Use 'const' instead deprecated G_CONST_RETURN
vteseq: Use 'const' instead deprecated G_CONST_RETURN

rvu95/vte,saitoha/vte-sixel,thestinger/vte-ng,jessevdk/vte,flaxandteal/gasket-vte,flaxandteal/gasket-vte,thestinger/vte-ng,thestinger/vte-ng,jessevdk/vte,rvu95/vte,flaxandteal/gasket-vte,flaxandteal/gasket-vte,rvu95/vte,jessevdk/vte,rvu95/vte,saitoha/vte-sixel,jessevdk/vte,saitoha/vte-sixel