Followup improvements to LSP (#11430)

Addressing things brought up in https://github.com/neovim/neovim/issues/11389 and beyond.

- Bugfix for empty dictionary serialization.
- Reduce markdown previews of code.
- Refactor method triggers to `lsp.buf.*` methods
- Switch to v:lua and get rid of vim interface.
- Get rid of filetype config in favor of something from https://github.com/neovim/nvim-lsp
- Switch error messages to something which doesn't require `ENTER` because if an LSP goes crazy, it'll block neovim.
- Rename `builtin_callbacks` to `default_callbacks`
- Resolve callback at time of calling using default_callbacks instead of at client creation
- Make hover/signatureHelp preview focusable so you can mess with it.
- Add vim.lsp.util.set_qflist and vim.lsp.util.set_loclist and vim.lsp.util.locations_to_items().
- Add apply_textedit and tests which enables a new class of features.
- Fix column offsets in character and bytes in vim.lsp.buf to be correct.

New methods:
- Add textDocument/references under vim.lsp.buf.references()
- Finish textDocument/rename
- Finish textDocument/rangeFormatting and textDocument/format

1 files changed, 5 insertions, 1 deletions

diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 446bbafc3c..ebe394f164 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -353,10 +353,14 @@ describe('lua stdlib', function()
 
   it('vim.list_extend', function()
     eq({1,2,3}, exec_lua [[ return vim.list_extend({1}, {2,3}) ]])
-    eq('Error executing lua: .../shared.lua: src must be a table',
+    eq('Error executing lua: .../shared.lua: src: expected table, got nil',
       pcall_err(exec_lua, [[ return vim.list_extend({1}, nil) ]]))
     eq({1,2}, exec_lua [[ return vim.list_extend({1}, {2;a=1}) ]])
     eq(true, exec_lua [[ local a = {1} return vim.list_extend(a, {2;a=1}) == a ]])
+    eq({2}, exec_lua [[ return vim.list_extend({}, {2;a=1}, 1) ]])
+    eq({}, exec_lua [[ return vim.list_extend({}, {2;a=1}, 2) ]])
+    eq({}, exec_lua [[ return vim.list_extend({}, {2;a=1}, 1, -1) ]])
+    eq({2}, exec_lua [[ return vim.list_extend({}, {2;a=1}, -1, 2) ]])
   end)
 
   it('vim.tbl_add_reverse_lookup', function()