Is your feature request about something that is currently impossible or hard to do? Please describe the problem.

The correct indent of help files with a mix of tabs and spaces may be hard to grasp as a contributing outsider, burdening maintainers with correcting these (as happened to @k-takata du to me in https://github.com/vim/vim/pull/15721/files#diff-49e1f1e8a3b17eb217ce251d8200c88a2c9dede55a4373df3d2176a8403f7f28 )

Describe the solution you'd like
Since there's now uniform formatting of source files, how about uniformizing the help file indents (with spaces rather than tabs, say)?

Describe alternatives you've considered
Document why tabs and spaces are needed and how to correctly employ them

Additional context
See above links