[clang-tools-extra] [clang] [clangd] Collect comments from function definitions into the index (PR #67802)

[Christian Kandeler via cfe-commits]

ckandeler wrote:

> Ok, I see. (I was confused because nothing in the patch looks at the contents of `Symbol::DocComment` other than 
> an `empty()` check; maybe a `bool HasDocComment` flag is sufficient?)

Right, we just need to save the information whether there was a doc comment before clangd put default values into the Documentation field. 

> I'll have a more detailed look when I get a chance, but one suggestion I wanted to make in the meantime: for 
> changes that add new information to the index, it helps to have a sense of how large of an increase to the index's 
> disk and memory footprint they entail. In the past, I've measured this with the LLVM codebase's index as a "test 
> case".

Will check.


https://github.com/llvm/llvm-project/pull/67802