PR template to clarify manual backport [ci skip]
PR template to clarify manual backport [ci skip]

astropy/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,pllim/astropy,larrybradley/astropy,larrybradley/astropy,saimn/astropy,mhvk/astropy,StuartLittlefair/astropy,pllim/astropy,StuartLittlefair/astropy,astropy/astropy,saimn/astropy,astropy/astropy,lpsinger/astropy,lpsinger/astropy,pllim/astropy,larrybradley/astropy,pllim/astropy,StuartLittlefair/astropy,larrybradley/astropy,lpsinger/astropy,lpsinger/astropy,saimn/astropy,mhvk/astropy,mhvk/astropy,astropy/astropy,larrybradley/astropy,saimn/astropy,saimn/astropy,mhvk/astropy,mhvk/astropy,pllim/astropy,astropy/astropy,lpsinger/astropy