Structure panel should omit "let () = ..." items and should include "let (a,b) = ..." items

[jfehrle]

plugin version: 0.73

1. Top level lets in the form let () = ... should not appear in the structure panel since they don't have name. For example:

2. Top level lets in the form let (a, b) = ... should appear in the structure panel with names a and b. For example:

Code for the examples is here: https://github.com/coq/coq/blob/master/vernac/vernacentries.ml

[giraud]

Fixed in 0.74

[jfehrle]

Looks better on # 1, thanks.

I would have split let (f_interp_redexp, interp_redexp_hook) into 2 separate entries in the structure panel. Both are top-level variables. They just happen to both be defined in the same let. If I'm looking for f_interp_redexp when the structure panel is alphabetized I'd expect to find it between focus_cmd_cond and get_current_context_of_args

Also, a different issue: I'd expect the opens to be alphabetized when the panel has alphabetic order selected. And probably I'd intermix them with other symbols.

[giraud]

Fixed in 0.75

[jfehrle]

Looks good!