docs/releasing: release.sh is located in xorg/util-modular
docs/releasing: release.sh is located in xorg/util-modular

Correct the silly typo s/macros/modular/ and add a reference to the
repository.

Signed-off-by: Emil Velikov <f20878473f414da183da19ee25c8722cc1d711e4@collabora.com>
Reviewed-by: Eric Engestrom <de0b63cf2dfb1fae8ed3c3b4244856a05677d4f0@imgtec.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler