[text] Avoid a Pango warning with empty markup
[text] Avoid a Pango warning with empty markup

When the markup string is empty Pango complains about invalid
characters.

spatulasnout/clutter,nobled/clutter,tardyp/clutter,collects/clutter,Distrotech/clutter,djdeath/clutter,tardyp/clutter,heysion/clutter-clone,Distrotech/clutter,djdeath/clutter-multithreaded,spatulasnout/clutter,GNOME/clutter,jigpu/clutter,dlespiau/clutter,heysion/clutter-clone,rkudiyarov/clutter_osx,jigpu/clutter,kerrickstaley/clutter-vala,djdeath/clutter,ebassi/clutter,djdeath/clutter-android,djdeath/clutter-multithreaded,djdeath/clutter-multithreaded,dlespiau/clutter,ebassi/clutter,collects/clutter,kerrickstaley/clutter-vala,spatulasnout/clutter,kerrickstaley/clutter-vala,djdeath/clutter-android,nobled/clutter,heysion/clutter-clone,kerrickstaley/clutter-vala,tardyp/clutter,jigpu/clutter,dlespiau/clutter,Distrotech/clutter,rkudiyarov/clutter_osx,jigpu/clutter,djdeath/clutter-android,collects/clutter,ebassi/clutter,GNOME/clutter,GNOME/clutter,GNOME/clutter,jigpu/clutter,djdeath/clutter-android,Distrotech/clutter,djdeath/clutter-android,Distrotech/clutter,heysion/clutter-clone,heysion/clutter-clone,collects/clutter,Distrotech/clutter,djdeath/clutter,ebassi/clutter,jigpu/clutter,djdeath/clutter,spatulasnout/clutter,ebassi/clutter,rkudiyarov/clutter_osx,rkudiyarov/clutter_osx,collects/clutter,djdeath/clutter,GNOME/clutter,nobled/clutter,djdeath/clutter,spatulasnout/clutter,djdeath/clutter-multithreaded