doc: move `cmake -B build -LH` up in Unix build docs

[kevkevinpal]

mentioned in: bitcoin#33088

"@stickies-v might follow up with any Windows doc changes." - fanquake

[frankomosh]

Hello @kevkevinpal . Thanks for compiling these.

Can I do the folloup to windows doc? or is someone already doing it?

[kevkevinpal]

Can I do the folloup to windows doc? or is someone already doing it?

Sure I don't see why not, from the last time I checked no one else is doing it but I'd check to see if a PR is up or merged first. But I'd say take a crack at it!

[frankomosh]

Great

[frankomosh]

Attempted here bitcoin#33789 .

[kevkevinpal]

Attempted here bitcoin#33789 .

Awesome! I'll close this issue thanks for posting and making the change!