docs(updating): add update guide

[spike-rabbit]

Adds a general update guide for element.

---

• I confirm that this MR follows the contribution guidelines.

[gemini-code-assist]

Code Review

The pull request adds a new update guide, which is a great addition. However, the structure of the guide could be confusing for users. The steps are not in a logical order, and it presents two different ng update commands, which could lead to errors. I've suggested a restructuring of the document to provide a clearer, step-by-step process for updating. The main points are to first update Angular, then Element, and to clarify what the automatic migration does versus what needs to be done manually.

[github-actions]

Documentation.
Examples.
Playwright report.

Coverage Reports:

• element-ng
• element-translate-ng

[spliffone]

Can we state which @simpl/brand version is necessary, since the consumer can only guess which major version to use

[github-actions]