Couple of `showLineNumbers` issues

[Liam Scott-Russell]

Hi there,

I've been enjoying setting up Vocs for my blog, but have run into these two issues so far.

I am using vocs 1.0.0-alpha.29

Both are with the default setup from the "Getting Started" section of the docs.
They're probably small CSS fixes, however I'm not great at CSS so I couldn't figure it out.

Issue 1 - Diff breaks numbering

Minimal Repro

(Remove the \ chars)

\```ts twoslash showLineNumbers
const hello = "world"; // [!code ++]
const secondLine = 2;
\```

Screenshot

Issue 2 - Hovering on code breaks numbering

Minimal Repro

(Remove the \ chars)

\```ts twoslash showLineNumbers
const hello = "world"
//    ^?
const secondLine = 2;
\```

Note that I am using // ^? to force the hover, however it will happen when hovering with the mouse.

Screenshot