Any way to have ".sh" be optional?

[TJ Luoma <luomat@xxxxxxxxx>]

The Subject line may not be the best description of what I want, but
it was the best I could come up with.

I tend to name all of my Zsh scripts to end with '.sh' so I can easily
`fgrep -i Whatever *.sh` when I'm looking for something.

However, I would rather not have to type the ".sh" if not necessary.
(Yes, I am that lazy.)

So assume I have a script "mkseries.sh" which I do not want to rename
but which I want to use in zsh just by typing "mkseries" -- is there a
way to tell zsh "If I use the command 'foo' and there is no 'foo' but
there is 'foo.sh' then I want to use 'foo.sh'?

As always, thanks for your time,

Tj


ps - I am only asking about this when using Zsh in Terminal as my
login shell; in shell scripts I don't mind adding the ".sh"