…var/let symbols
fixes#22939fixes#16890
Besides, it was applied to let/const/var with pragmas, now it is
universally applied.
```nim
{.push exportc.}
proc foo =
let bar = 12
echo bar
{.pop.}
```
For example, the `bar` variable will be affected by `exportc`.
* [sugar] handle HiddenDeref in capture, error at CT if unsupported nnk
Instead of running into trouble of the `.strVal` access failing, it's
better to error at CT.
* [tests] remove unnecessary import in test case
* improve ident extraction & extend test cases
* [tests] improve tests for `capture` of different types & act. check
* make more standard libraries work with `nimPreviewSlimSystem`
* typo
* part two
* Delete specutils.nim
* fixes more tests
* more fixes
* fixes tests
* fixes three more tests
* add formatfloat import
* fix
* last
