[doc] Cherrypicks dev install doc changes into v1.3.0 release branch#6761

Merged

ailzhang merged 2 commits intotaichi-dev:rc-v1.3.0from ailzhang:cherry-pick-dev-install

Nov 30, 2022

+16-100

Commits on Nov 29, 2022

[doc] Update LLVM10 -> LLVM15 in installation guide (taichi-dev#6747 )

jim19930609
authored and
Ailing Zhang
committed
[doc] Update dev install about clang version (taichi-dev#6759 )

authored and
Ailing Zhang
committed