Built-in LSP Declaration Handler

[Isrothy]

Is your feature request related to a problem? Please describe.
While there are handlers for goto definition, references, and others, goto declaration is missing.

Describe the solution you'd like
I would like Telescope to include a built-in goto declaration handler for LSP, similar to its existing lsp_definitions and lsp_references pickers.

Describe alternatives you've considered

1. Using Neovim’s built-in vim.lsp.buf.declaration() function directly, but this does not integrate well with Telescope’s interface.
2. Relying on external plugins, though this adds complexity and redundancy.
3. Mapping vim.lsp.buf.declaration() to a Telescope picker manually, but this is not user-friendly for less experienced users.

Additional context
This feature would be particularly helpful in languages where declarations and definitions are in separate locations, such as C/C++ or Go