Should close#8704.
# Description
this PR
- makes the error thrown by things like `ansi -e {invalid: "invalid"}`
more explicit
- makes the `ansi -e` example more explicit about valid / invalid keys
# User-Facing Changes
the error
```bash
> ansi -e {invalid: "invalid"}
Error: nu:🐚:incompatible_parameters
× Incompatible parameters.
╭─[entry #1:1:1]
1 │ ansi -e {invalid: "invalid"}
· ──────────┬─────────
· ╰── unknown ANSI format key: expected one of ['fg', 'bg', 'attr'], found 'invalid'
╰────
```
the new `ansi -e` example
```bash
Use structured escape codes
> let bold_blue_on_red = { # `fg`, `bg`, `attr` are the acceptable keys, all other keys are considered invalid and will throw errors.
fg: '#0000ff'
bg: '#ff0000'
attr: b
}
$"(ansi -e $bold_blue_on_red)Hello Nu World(ansi reset)"
Hello Nu World
```
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- ⚫ `toolkit test`
- ⚫ `toolkit test stdlib`
# After Submitting
```
$nothing
```
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