Templates support in DCD

[ryuukk_]

Hello,

What annoys me the most about D is the tooling, specially the 
lack of solid IDE support, i understand it's very hard to do, so 
i don't complain much about it, instead i try to contribute as 
much as i can

So last week i decided it was time to attempt something, so the 
past week i have been working on adding proper support for 
templates in DCD

It's been quite difficult, as expected, but i have been able to 
come up with a decent PR!

So far it's working nicely in my huge project, but i do not use 
templates a lot, only for containers

So if you have a big project and consume a lot of templates, 
please give my PR a try and let me know what works, what doesn't 
and what could be improved!

If you can, i'd love to get a code review too, that would be 
helpful!


Here is the PR: https://github.com/dlang-community/DCD/pull/714

PS: If you use the vscode extension, you'll need to change the 
version here:

https://github.com/dlang-community/DCD/blob/master/common/src/dcd/common/dcd_version.d#L29

Replace it with "v9.9.9", so serve-d won't complain about the 
version

Works with auto :)

![screenshot](https://i.imgur.com/fwETSMH.png)