[Feature] Add Listing symbols

[xdavidel]

I think we can achieve listing symbols for the current buffer / workspace pretty easily.
I found the following command and I think we can implement something similar in lua:

cscope -R -L -2 ".*" | awk -F ' ' '{print $2 "#" $1}' | sort | uniq

What do you think @dhananjaylatkar?

[dhananjaylatkar]

This command is very slow. Did you try it on a large codebase?

I remember using this cmd on linux source and it took more than 5mins.

[xdavidel]

This command is very slow. Did you try it on a large codebase?

I remember using this cmd on linux source and it took more than 5mins.

Mmm I would say medium size...
I can try something bigger like Linux source.

I guess we can cache the result - since cscope database is static anyway.