Rename lock method for DesignManagement::Version

It is now named `with_lock`, and its use is described in the comment on
`.create_for_designs`.

ee/app/models/design_management/version.rb

@@ -66,6 +66,10 @@ module DesignManagement
     # designs, and not being able to add designs without a saved version. Also this
     # method inserts designs in bulk, rather than one by one.
     #
+    # Before calling this method, callers must guard against concurrent
+    # modification by obtaining the lock on the design repository. See:
+    # `DesignManagement::Version.with_lock`.
+    #
     # Parameters:
     # - design_actions [DesignManagement::DesignAction]:
     #     the actions that have been performed in the repository.
@@ -98,8 +102,8 @@ module DesignManagement
     CREATION_TTL = 5.seconds
     RETRY_DELAY = ->(num) { 0.2.seconds * num**2 }
 
-    def self.lock_for_creation(project_id, repository, &block)
-      key = "lock_for_creation:#{name}:{#{project_id}}"
+    def self.with_lock(project_id, repository, &block)
+      key = "with_lock:#{name}:{#{project_id}}"
 
       in_lock(key, ttl: CREATION_TTL, retries: 5, sleep_sec: RETRY_DELAY) do |_retried|
         repository.create_if_not_exists

ee/app/services/design_management/delete_designs_service.rb

@@ -37,7 +37,7 @@ module DesignManagement
     attr_reader :designs
 
     def delete_designs!
-      DesignManagement::Version.lock_for_creation(project.id, repository) do
+      DesignManagement::Version.with_lock(project.id, repository) do
         run_actions(build_actions)
       end
     end

ee/app/services/design_management/save_designs_service.rb

@@ -33,7 +33,7 @@ module DesignManagement
     attr_reader :files
 
     def upload_designs!
-      ::DesignManagement::Version.lock_for_creation(project.id, repository) do
+      ::DesignManagement::Version.with_lock(project.id, repository) do
         actions = build_actions
 
         [actions.map(&:design), actions.presence && run_actions(actions)]