track comptime types

[mfield]

Adds some tracking of comptime types.

changes formatting for comptime structs, e.g. HashMap(...) -> HashMap(i32,void). maybe just a preference of mine? but i like seeing it. could easily change the formatter back to ....

fixes:

• repeated use of the same comptime function Allocator usage causes zls inline types to get very confused #1841
• nested generic structs e.g. incorrect completions on nested generic type like std.ArrayList #1392

[mfield]

sorry for the false start. saw something while reading the diff and made a small change last second without re-building :(
new version is passing tests again!