candy machine docs changes for cu

[jim4067]

With Core, I don't think requestion 800_000 compute units is reasonable.

Remove the paragraph from the basic minting section and introduced it in minting with guards

Reduce initial requested CUs to 300k

Here is the transaction for a basic mint from a core CM using the sol guard using less that 80k CUs

[vercel]

@jim4067 is attempting to deploy a commit to the Metaplex Foundation Team on Vercel.

A member of the Team first needs to authorize it.

[danenbm]

Thank you for the PR! LGTM except could you please switch back to 2 space indent for the example code?

[jim4067]

updated @danenbm