Bug 53290: Add descriptive titles for edit/rename buttons in editor.

The edit/create/rename buttons in the JSON editor did not have
title attributes, so there was no description of the action they
were performing. This patch adds these.

Bug: 53290
Change-Id: I65e0e0dff4ff6a2c95e493cd68547be2b485e4fb
Merge "Bug 53290: Add descriptive titles for edit/rename buttons in editor."