Add expected haddock failure for hledger-web.
Add expected haddock failure for hledger-web.

Please see https://github.com/fpco/stackage/issues/2187.

soenkehahn/stackage,ethercrow/stackage,spencerjanssen/stackage,lwm/stackage,fpco/stackage,athanclark/stackage,mgajda/stackage,mrkkrp/stackage,Shimuuar/stackage,peti/stackage,int-index/stackage,k0ral/stackage,jonschoning/stackage,ygale/stackage,mstksg/stackage,michalkonecny/stackage,iand675/stackage,wereHamster/stackage,phaazon/stackage,stackbuilders/stackage,simonmichael/stackage,creichert/stackage,massysett/stackage,fimad/stackage,christiaanb/stackage,judah/stackage,clinty/stackage,DanielG/stackage,garetxe/stackage,asr/stackage,alanz/stackage,phadej/stackage,GregorySchwartz/stackage,Daniel-Diaz/stackage