feat: add segment elfeed

[idlip]

• with elfeed-search buffer open, it indicates the unread feeds count shown upon filter activated.

Hi @liuyinz

I had wrote and used elfeed segment way back, thought to just add it here also.

• Basically I have added in simple way of using function used by elfeed package itself, con is that it needs elfeed buffer to be open.

• I have also trimmed the output string to only represent the unread feeds count. Default output is:

  100/140:10

  • where, 100 is unread count out of filtered list

  • 140 is the filtered feeds list

  • 10 is the feed names

  • So trim only gives 100, I thought it was sensible and reduces space for echo area.

[liuyinz]

@idlip I rewrite the segment in f54799741131527ff6e200795b9f288ddc6d93c5

• rename it to "elfeed-unread"
• only show info when the unread is a number and > 0
• add prefix "elfeed", it's not a everyone needed segment like flymake,size..., and if only a num provided would be quite confusing How do you think?

[idlip]

It looks good to me.

In my config, to minimize text I use icons instead.

All good, thank you for fixing the segment!

[liuyinz]

I rename to elfeed finally, and thanks your pr.