Syntax Highlighting broken for inline command completions

[jamesonknutson]

Nushell 0.108.0 adds support for a simpler completion syntax. See more here: https://www.nushell.sh/blog/2025-10-15-nushell_v0_108_0.html#simple-syntax-for-simple-completions-16789-toc

Right now, syntax highlighting breaks when using that simple syntax. We should add support for this new syntax, so that it looks as expected.

Here is an example of what I mean:

[fdncred]

We should add support for this new syntax, so that it looks as expected.

Go for it. We'd accept a PR for it. It would be good to add this before the latest pre-release changes to release.