[clang-tools-extra] [clangd] Fix crash on completion with out-of-range position (PR #196112)

[Krzysztof Jędruczyk via cfe-commits]

kjedruczyk wrote:

Re-reading your comment, maybe you were suggesting it's cleaner to just consume this error via vlog - which I thought at first, but was worried that it doesn't include the same details. I can still add it there, but I imagine it would be best to keep the file and offset details.

https://github.com/llvm/llvm-project/pull/196112