fix(lsp): set end_col in formatexpr (#19676)

The last line was excluded from formatting via formatexpr because the
character in the params was set to 0 instead of the end of line.

runtime/lua/vim/lsp.lua

@@ -1982,29 +1982,32 @@ function lsp.formatexpr(opts)
     return 1
   end
 
-  local start_line = vim.v.lnum
-  local end_line = start_line + vim.v.count - 1
+  local start_lnum = vim.v.lnum
+  local end_lnum = start_lnum + vim.v.count - 1
 
-  if start_line > 0 and end_line > 0 then
-    local params = {
-      textDocument = util.make_text_document_params(),
-      range = {
-        start = { line = start_line - 1, character = 0 },
-        ['end'] = { line = end_line - 1, character = 0 },
+  if start_lnum <= 0 or end_lnum <= 0 then
+    return 0
+  end
+  local bufnr = api.nvim_get_current_buf()
+  for _, client in pairs(lsp.get_active_clients({ bufnr = bufnr })) do
+    if client.supports_method('textDocument/rangeFormatting') then
+      local params = util.make_formatting_params()
+      local end_line = vim.fn.getline(end_lnum)
+      local end_col = util._str_utfindex_enc(end_line, nil, client.offset_encoding)
+      params.range = {
+        start = {
+          line = start_lnum - 1,
+          character = 0,
+        },
+        ['end'] = {
+          line = end_lnum - 1,
+          character = end_col,
         },
       }
-    params.options = util.make_formatting_params().options
-    local client_results =
-      vim.lsp.buf_request_sync(0, 'textDocument/rangeFormatting', params, timeout_ms)
-
-    -- Apply the text edits from one and only one of the clients.
-    for client_id, response in pairs(client_results) do
+      local response =
+        client.request_sync('textDocument/rangeFormatting', params, timeout_ms, bufnr)
       if response.result then
-        vim.lsp.util.apply_text_edits(
-          response.result,
-          0,
-          vim.lsp.get_client_by_id(client_id).offset_encoding
-        )
+        vim.lsp.util.apply_text_edits(response.result, 0, client.offset_encoding)
         return 0
       end
     end

runtime/lua/vim/lsp/util.lua

@@ -113,7 +113,7 @@ end
 --- Convert byte index to `encoding` index.
 --- Convenience wrapper around vim.str_utfindex
 ---@param line string line to be indexed
----@param index number byte index (utf-8), or `nil` for length
+---@param index number|nil byte index (utf-8), or `nil` for length
 ---@param encoding string utf-8|utf-16|utf-32|nil defaults to utf-16
 ---@return number `encoding` index of `index` in `line`
 function M._str_utfindex_enc(line, index, encoding)