Adding missing document files.

	new file:   pgtesttiming.sgmlin
	new file:   rangetypes.sgmlin
	new file:   ref/pg_receivexlog.sgmlin
	new file:   release-9.2.sgmlin
	new file:   release-xc-1.1.sgmlin
	new file:   spgist.sgmlin
	new file:   tcn.sgmlin