fix(core) Include causes when converting anyhow errors to JS exceptions (#16397)

When an op returns an `anyhow` error with a cause (usually added using
the `.context()` method), the `Error` thrown into JavaScript contains
only the message of the outernmost error in the chain.

This PR simply changes the formatting of `anyhow::Error` from `"{}"` to
`"{:#}"`:

This significantly improves errors for code that embeds Deno and defines
custom ops. For example, in
[chiselstrike/chiselstrike](https://github.com/chiselstrike/chiselstrike),
this PR improves an error message like

```
Error: could not plan migration
```

to

```
Error: could not plan migration: could not migrate table for entity "E": could not add column for field "title": the field does not have a default value
```

1 files changed, 1 insertions, 1 deletions

diff --git a/core/error.rs b/core/error.rs
index 5ee3355c4..9ad99c6da 100644
--- a/core/error.rs
+++ b/core/error.rs
@@ -105,7 +105,7 @@ pub fn to_v8_error<'a>(
   let cb = cb.open(scope);
   let this = v8::undefined(scope).into();
   let class = v8::String::new(scope, get_class(error)).unwrap();
-  let message = v8::String::new(scope, &error.to_string()).unwrap();
+  let message = v8::String::new(scope, &format!("{:#}", error)).unwrap();
   let mut args = vec![class.into(), message.into()];
   if let Some(code) = crate::error_codes::get_error_code(error) {
     args.push(v8::String::new(scope, code).unwrap().into());