Move plugin
Though listed among the Admin plugins, this does have one function open to all editors, that of renaming the current page and updating all links to it. This come in handy when one makes a mistake in naming a page or assigns it to the wrong namespace.
Basic use
When this plugin is installed, an additional button is visible in the group under the Edit Page button at the right of the page. It looks like a paint roller.
Clicking that button opens a dialog where the editor can adjust the page's name.
Admin use
The plugin is also available on the Administration page, under the “Additional Plugins” heading as “Move pages and namespaces”. Clicking that opens a page where either the current or current namespace can be renamed. Again, this adjusts all of the links elsewhere in the wiki that pointed to the old page(s).
A link there goes to a tree-based, drag-and-drop view of the whole wiki for even more involved reorganization. The current editor just noticed that for the first time while writing this. Huh.