Minor clarifications for chapters 10 and 12

[talosgl]

Proposing two minor edits to the book to improve clarity:

• Chapter 10: Clarifies that the sort() method operates in-place and does not return a new list.
• Chapter 12: Adds a reference to urllib as the HTTP-focused library, to distinguish it from socket mentioned earlier in the chapter.

Changes are intended to help avoid small but common points of confusion for new learners.