feat(lsp): options to filter and auto-apply code actions (#18221)

Implement two new options to vim.lsp.buf.code_action():
 - filter (function): predicate taking an Action as input, and returning
   a boolean.
 - apply (boolean): when set to true, and there is just one remaining
   action (after filtering), the action is applied without user query.

These options can, for example, be used to filter out, and automatically
apply, the action indicated by the server to be preferred:

    vim.lsp.buf.code_action({
        filter = function(action)
            return action.isPreferred
        end,
        apply = true,
    })

Fix #17514.

1 files changed, 18 insertions, 8 deletions

diff --git a/runtime/doc/lsp.txt b/runtime/doc/lsp.txt
index b704d2d6e8..bf4c2b59d1 100644
--- a/runtime/doc/lsp.txt
+++ b/runtime/doc/lsp.txt
@@ -969,18 +969,28 @@ add_workspace_folder({workspace_folder})
 clear_references()                            *vim.lsp.buf.clear_references()*
                 Removes document highlights from current buffer.
 
-code_action({context})                             *vim.lsp.buf.code_action()*
+code_action({options})                             *vim.lsp.buf.code_action()*
                 Selects a code action available at the current cursor
                 position.
 
                 Parameters: ~
-                    {context}  table|nil `CodeActionContext` of the LSP specification:
-                               • diagnostics: (table|nil) LSP`Diagnostic[]` . Inferred from the current position if not
-                                 provided.
-                               • only: (string|nil) LSP `CodeActionKind` used
-                                 to filter the code actions. Most language
-                                 servers support values like `refactor` or
-                                 `quickfix`.
+                    {options}  table|nil Optional table which holds the
+                               following optional fields:
+                               • context (table|nil): Corresponds to `CodeActionContext` of the LSP specification:
+                                 • diagnostics (table|nil): LSP`Diagnostic[]` . Inferred from the current position if not
+                                   provided.
+                                 • only (string|nil): LSP `CodeActionKind`
+                                   used to filter the code actions. Most
+                                   language servers support values like
+                                   `refactor` or `quickfix`.
+
+                               • filter (function|nil): Predicate function
+                                 taking an `CodeAction` and returning a
+                                 boolean.
+                               • apply (boolean|nil): When set to `true`, and
+                                 there is just one remaining action (after
+                                 filtering), the action is applied without
+                                 user query.
 
                 See also: ~
                     https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_codeAction