[clangd] Fix handling of inline/anon namespaces and names of deduced types in hover

[clangd] Fix handling of inline/anon namespaces and names of deduced types in hover

Summary:
Clangd normally skips inline and anon namespaces while printing nested name
specifiers. It also drops any tag specifiers since we make use of `HoverInfo::Kind`
instead of some text in `HoverInfo::Name`

There was a bug causing us to print innermost inline/anon namespace, this patch
fixes that by skipping those.
Also changes printing and kind detection of deduced types to be similar to decl
case.

Also improves printing for lambdas, currently clangd prints lambdas as
`(anonymous class)`, we can improve it by at least printing `(lambda)`
instead.

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71543