Support filter_items

[TmLev]

Description

This PR aims to add support for generic items filtering mechanism as described in #3401.

Resolves #3401.

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

local map = function(keys, func, desc, mode)
  mode = mode or 'n'
  vim.keymap.set(mode, keys, func, { 
    -- buffer = event.buf, -- `LspAttach` event (taken from `kickstart.nvim`)
    desc = 'LSP: ' .. desc 
  })
end

map('gd', function()
  require('telescope.builtin').lsp_definitions {
    filter_items = function(items)
      return items -- Test A: Returns all results.
      -- return {} -- Test B: Returns nothing, displaying the `No LSP Definitions found` message.
    end,
  }
end, '[G]oto [D]efinition')

Configuration:

• Neovim version (nvim --version):

  NVIM v0.10.3
  Build type: Release
  LuaJIT 2.1.1734355927
  

• Operating system and version: macOS 13.4

Checklist:

• My code follows the style guidelines of this project (stylua)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas There is no hard-to-understand code
• I have made corresponding changes to the documentation (lua annotations)