[Mac/iOS/GN] Document enable_stripping and enable_dsyms vs their GYP equivalents.

BUG=330301
R=brettw@chromium.org

Review-Url: https://codereview.chromium.org/2084153002
Cr-Original-Commit-Position: refs/heads/master@{#401320}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d6fd033cbaddd2f127b244c48a3cfd8f7a3e953d
diff --git a/tools/gn/docs/cookbook.md b/tools/gn/docs/cookbook.md
index 687d9eb..942b572 100644
--- a/tools/gn/docs/cookbook.md
+++ b/tools/gn/docs/cookbook.md
@@ -222,6 +222,8 @@
 | `mac_sdk_min`                                   | `mac_sdk_min`                              | `//build/config/mac/mac_sdk.gni`               |
 | `mac_sdk_path`                                  | `mac_sdk_path`                             | `//build/config/mac/mac_sdk.gni`               |
 | `mac_sdk`                                       | `mac_sdk_version`                          | `//build/config/mac/mac_sdk.gni`               |
+| `mac_strip_release`                             | `enable_stripping`                         | `//build/config/mac/symbols.gni`               |
+| `mac_want_real_dsym`                            | `enable_dsyms`                             | `//build/config/mac/symbols.gni`               |
 | `msan` (0/1)                                    | `is_msan` (true/false)                     | `//build/config/sanitizers/sanitizers.gni`     |
 | `SDKROOT` (Mac)                                 | `sysroot`                                  | `//build/config/sysroot.gni`                   |
 | `sysroot`                                       | `sysroot`                                  | `//build/config/sysroot.gni`                   |