Mark requireChangeId as deprecated

This lets us remove it in Gerrit 3.0.

Change-Id: Ie5cd0c2b5d4aa9bd4579b4bf64366c68552fbdee
diff --git a/Documentation/config-project-config.txt b/Documentation/config-project-config.txt
index cad9489..9c8181b 100644
--- a/Documentation/config-project-config.txt
+++ b/Documentation/config-project-config.txt
@@ -127,7 +127,11 @@
 +
 Controls whether or not the Change-Id must be included in the commit message
 in the last paragraph. Default is `INHERIT`, which means that this property
-is inherited from the parent project.
+is inherited from the parent project. The global default for new hosts
+is `true`
++
+This option is deprecated and future releases will behave as if this
+is always `true`.
 
 [[receive.maxObjectSizeLimit]]receive.maxObjectSizeLimit::
 +
diff --git a/Documentation/rest-api-projects.txt b/Documentation/rest-api-projects.txt
index 22d4f06..f32480b 100644
--- a/Documentation/rest-api-projects.txt
+++ b/Documentation/rest-api-projects.txt
@@ -2893,7 +2893,8 @@
 link:#inherited-boolean-info[InheritedBooleanInfo] that tells whether a
 valid link:user-changeid.html[Change-Id] footer in any commit uploaded
 for review is required. This does not apply to commits pushed directly
-to a branch or tag.
+to a branch or tag. This property is deprecated and will be removed in
+a future release.
 |`enable_signed_push`|optional, not set if signed push is disabled|
 link:#inherited-boolean-info[InheritedBooleanInfo] that tells whether
 signed push validation is enabled on the project.
@@ -2985,6 +2986,8 @@
 directly to a branch or tag. +
 Can be `TRUE`, `FALSE` or `INHERIT`. +
 If not set, this setting is not updated.
+This property is deprecated and will be removed in
+a future release.
 |`reject_implicit_merges`                  |optional|
 Whether a check for implicit merges will be performed when changes
 are pushed for review. +
@@ -3352,6 +3355,8 @@
 |`require_change_id`                           |`INHERIT` if not set|
 Whether the usage of Change-Ids is required for the project (`TRUE`,
 `FALSE`, `INHERIT`).
+This property is deprecated and will be removed in
+a future release.
 |`max_object_size_limit`     |optional|
 Max allowed Git object size for this project.
 Common unit suffixes of 'k', 'm', or 'g' are supported.