[JonChesterfield]

After a slightly dubious use of time, I can confirm that columns is not necessary. Also noticed that the original version missed double_colon:: style targets. I fear sort is not necessary either but one has to draw the line somewhere.

  HELP_PADDING := 30
  
  .PHONY: awkhelp
  awkhelp: ## Write this help using awk
   @echo "awkhelp:"
   @awk 'BEGIN {FS = ":.*#+"}; /^[a-zA-Z_*.-]+:.*## .*$$/ {printf "  %-'$(HELP_PADDING)'s %s\n", $$1, $$2}' \
   $(MAKEFILE_LIST) | \
   sort
  
  .PHONY: sedhelp
  sedhelp: ## Write this help using sed
   @echo "sedhelp:"
   @sed -E \
   -e '/^([a-zA-Z_*.-]+::?[ ]*)##[ ]*([^#]*)$$/ !d # grep' \
   -e 's/([a-zA-Z_*.-]+:):?(.*)/  \1\2/ # drop :: and prefix pad' \
   -e ':again s/^([^#]{1,'$(HELP_PADDING)'})##[ ]*([^#]*)$$/\1 ##\2/ # insert a space' \
   -e 't again # do it again (termination is via {1, HELP_PADDING})' \
   -e 's/^([^#]*)##([^#]*)$$/\1\2/ # remove the ##' \
   $(MAKEFILE_LIST) | \
   sort