Add option to keep \[ ... \] on one line

[evlasics]

Is your feature request related to a problem? Please describe it.
When I do the surround.vim bindings to change a math environment to \[, it automatically places the output on three lines. So for example, if we had a file (* is the cursor)

We can prove \( \pi >* \frac{22}{7} \) with calculus.

then hitting cse\[<C-r> converts this into

We can prove
\[
     \pi >* \frac{22}{7}
\]
with calculus.

whereas it's common to place these all on one line instead:

We can prove
\[ \pi >* 3 \]
with calculus.

Describe the solution you'd like
Ideally, some way of configuring the default behavior to match the second example

Describe alternatives you've considered
I could manually remove the newlines (mbkJJ`b to preserve cursor position in the line), but this loses me precious keystrokes, which are not always plentiful if I need to work very quickly.

Additional context
I know that for some people, the original behavior is their preferred behavior, which is why I think it should be configurable.

[lervag]

whereas it's common to place these all on one line instead

VimTeX is 13 years old, and this feature has not been requested until now, so I'm not sure I would agree "it's common" here. Are you sure you really need or want it? What's the drawback of the current behaviour, and what's the benefit of not splitting into three lines?

The main reasoning of the current behaviour is to make the change between the displaymath variant \[...\] more natural, e.g. transitioning from \[...\] to a full equation environment doesn't change the actual equation line(s). This is also a benefit wrt. git changelogs, for instance.

[lervag]

See also #3040 for a related issue.

[lervag]

I'm generally reluctant to add options, but if I were to do it, it would be something like this:

" Targets that should be kept on a single line when changing environment
let g:vimtex_env_change_oneline = ['\[']

The default value should be [], i.e. the current behaviour. With '\[' in the list, cse\[ on your example would give:

We can prove
\[ \pi > \frac{22}{7} \]
with calculus.

Note that this would apply to ts$ as well.

However, I'm not 100% sure I want to add this.