[Feature] Support spaces before and after variable substitution

[primeapple]

Is your feature request related to a problem? Please describe.
IntelliJ HTTP client accepts the following

GET {{ api }}/path/12345

Kulala interpretes the spaces as part of the variable name:

GET %7B%7B%20api%20%7D%7D/path/12345

Describe the solution you'd like
Strip leading and trailing spaces before doing variable substitution.

[gorillamoe]

I'm not a big fan of completely diverging from the "default" that jetbrains and visual studio support:

https://www.jetbrains.com/help/idea/http-client-variables.html#environment-variables

So unless they both support that, I would refrain from adding this just for Kulala. Do you have a different take on that @YaroSpace ?

[YaroSpace]

I am generally in favour of trimming whitespace, as it tends to cause subtle errors, so I am actually in favour of this one too.

[gorillamoe]

Do we know if this would be still compatible to run in Jetbrains then?

ah nevermind, I'm done for today. I just read OP again and Jetbrains already does this. so just scrap everything I said before.

[primeapple]

Yes, Jetbrains has this by default.

Thanks for the quick fix!