framebuffer: Fix a closing tag in the documentation
framebuffer: Fix a closing tag in the documentation

This was causing the DocBook for the documentation to be invalid so
all of the framebuffer documentation disappeared.

Reviewed-by: Robert Bragg <12e9293ec6b30c7fa8a0926af42807e929c1684f@linux.intel.com>

gcampax/cogl,gcampax/cogl,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,Distrotech/cogl,Distrotech/cogl,djdeath/cogl-android,gcampax/cogl,djdeath/cogl,djdeath/cogl-android