menu-item, help-echo conventions

[Glenn Morris]

There seem to be some (unwritten?) conventions for menu-items and
their help texts:

i) Capitalize all non-trivial words in a menu item. E.g. in "Files":
"New Frame on Display".

ii) In menu-item help text, start with a capital, use the imperative,
don't end with a full-stop; e.g. "Insert another file into current
buffer".

Is that correct?

Some places violate these conventions, e.g.: "Edit" "Paste from kill
menu" rather than "Paste from Kill Menu"; "Edit" "Select All" has
help-text that ends in a full-stop; etc.

Some other things are inconsistent, e.g. in the "Options" menu, the
help-text for Auto Fill uses a capital "Mode", but in the entry for
"Blinking Cursor", a lower-case "mode" is used. It seems the latter is
preferred?

Obviously not critical, but if the above are the actual conventions,
it would be nice to document them somewhere (tips.texi?), and to fix
incorrect instances as they are noticed.