Expand error squiggles that start on # or < e.g. for #include <string.h>

[sean-mcmanus]

Repro with

#include <string.h>

With clang-tidy with all checks enabled.

IntelliSense error squiggles may potentially have the same issue in some cases too, but I'm not sure of a repro.

[bobbrow]

We’re closing this as not planned.
This issue has been inactive for a long time, and we will be unable to investigate and address it in the foreseeable future.