fix ruff/Ruff duplication

lua/plugins/none-ls.lua

@@ -45,6 +45,17 @@ return {
 
     -- Note: Diagnostics (linters) moved to nvim-lint plugin
 
+    -- Custom ruff formatter (ruff format subcommand)
+    local ruff_format = {
+      method = null_ls.methods.FORMATTING,
+      filetypes = { "python" },
+      generator = null_ls.formatter({
+        command = find_executable({ "ruff" }) or "ruff",
+        args = { "format", "--stdin-filename", "$FILENAME", "-" },
+        to_stdin = true,
+      }),
+    }
+
     null_ls.setup({
       sources = {
         -- Prettier (JS, TS, CSS, SCSS, JSON, Markdown, HTML)
@@ -75,10 +86,8 @@ return {
           command = find_executable({ "stylua" }),
         }),
 
-        -- black (Python)
-        formatting.black.with({
-          command = find_executable({ "black" }),
-        }),
+        -- ruff (Python formatter - custom since not in builtins)
+        ruff_format,
       },
 
       -- Format on save