gitignore: Add generated *.pot files in po/ subdirectory
gitignore: Add generated *.pot files in po/ subdirectory

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