doc: git-reset: reorder the forms

doc: git-reset: reorder the forms

From user feedback: three users commented that the `git reset [mode]`
form is the one that they primarily use, and that they were suprised to
see it listed last.
("I've never used git reset in any mode other than --hard").

Move it to be first, since the `git reset [mode]` form is what
"Reset current HEAD to the specified state" at the beginning refers
to, and because the `git reset [mode]` form is the only thing that
`git reset` uniquely does, the others could also be done with
`git restore`.

Signed-off-by: Julia Evans <redacted>
Signed-off-by: Junio C Hamano <redacted>
Signed-off-by: D. Ben Knoble <redacted>
Signed-off-by: Junio C Hamano <redacted>