Add notes about output dtype from block_replicate and block_reduce
Add notes about output dtype from block_replicate and block_reduce

larrybradley/astropy,astropy/astropy,mhvk/astropy,larrybradley/astropy,astropy/astropy,mhvk/astropy,pllim/astropy,pllim/astropy,lpsinger/astropy,larrybradley/astropy,larrybradley/astropy,pllim/astropy,astropy/astropy,mhvk/astropy,astropy/astropy,astropy/astropy,mhvk/astropy,mhvk/astropy,lpsinger/astropy,lpsinger/astropy,pllim/astropy,lpsinger/astropy,lpsinger/astropy,larrybradley/astropy,pllim/astropy