Macs don't use backslashes as path separators

Review-Url: https://codereview.chromium.org/2402033002
Cr-Original-Commit-Position: refs/heads/master@{#423938}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: e0088f675519c6e1c90ff0717f09fb267d8a0e5f

config/mac/mac_sdk.gni

@@ -16,8 +16,8 @@ declare_args() {
   # Minimum supported version of OSX.
   mac_deployment_target = mac_deployment_target_build_override
 
-  # Path to a specific version of the Mac SDK, not including a backslash at
-  # the end. If empty, the path to the lowest version greater than or equal to
+  # Path to a specific version of the Mac SDK, not including a slash at the end.
+  # If empty, the path to the lowest version greater than or equal to
   # mac_sdk_min is used.
   mac_sdk_path = ""