Skip annotating invalid frames

This is useful for stack traces that have more information than the `file:line count` format. For example, the [Nix language's evaluator profiler](https://github.com/NixOS/nix/pull/13220) also includes information about the function being called, which sometimes has a non-canonical call site location and therefore cannot be annotated. Here is how this might look like: ```log <nix/derivation-internal.nix>:37:12:primop derivationStrict ``` As such, with this change, we effectively skip annotating frames that don't conform to the `file:line count` format.  Code portion from the [NGIpkgs overview](https://github.com/ngi-nix/ngipkgs/blob/4810584e62513da39b5cdee18ffb4aef4865a982/overview/default.nix#L238).