[llvm] [llvm][Docs] Improve the formatting of the Common Problems section (PR #108522)

[David Spickett via llvm-commits]

DavidSpickett wrote:

With the added spacing it renders them like:

* `-G Ninja`

Setting this option will allow you to build with ninja instead of make. Building with ninja significantly improves your build time, especially with incremental builds, and improves your memory usage.

https://github.com/llvm/llvm-project/pull/108522