Refs #24158
Fixes the line info of the module symbol (cases like `import as` and
grouped imports had wrong line info). Since that symbol's line info is
now used for the warnings, there isn't a separate line info stored for
`unusedImports`
Examples of fixed cases
```nim
import strutils as test #[
^ before
^ after ]#
# This case was fixed by #24158, but only for unused imports
import std/[strutils, strutils] #[
^ before
^ after ]#
from strutils import split #[
^ before
^ after ]#
```
When importing from subdirectories, the line info used in `UnusedImport`
warning would be the `/` node and not the actual module node. More
obvious with grouped imports where all unused imports would show the
same column
Fix is to just use the last child node for infixes when getting the line
info
* clean up some test categories
* mention exact slice issue
* magics into system
* move trangechecks into overflow
* move tmemory to system
* try fix CI
* try fix CI
* final CI fix
