Merge bitcoin#29947: doc: Suggest only necessary Qt packages for installation on OpenBSD

970cbc3 doc: Suggest only necessary Qt packages for installation on OpenBSD (Hennadii Stepanov)

Pull request description:

  The currently suggested `qt5` installs many unneeded dependencies, for example, `qtsensors`, `qtspeech` etc.

  Similar to bitcoin#29932.

ACKs for top commit:
  theStack:
    re-ACK 970cbc3

Tree-SHA512: c680a4f88c27cae145822f30d9856fe76b856c6b11babe652c7171f4322dbe7af8725cccf8b45295067690ed98aa3f6329a8b65a59f31348854638ac375372d1

Author: fanquake

doc/build-openbsd.md

@@ -1,6 +1,6 @@
 # OpenBSD Build Guide
 
-**Updated for OpenBSD [7.4](https://www.openbsd.org/74.html)**
+**Updated for OpenBSD [7.5](https://www.openbsd.org/75.html)**
 
 This guide describes how to build bitcoind, command-line utilities, and GUI on OpenBSD.
 
@@ -63,7 +63,7 @@ export BDB_PREFIX="/path/to/bitcoin/depends/x86_64-unknown-openbsd"
 Bitcoin Core includes a GUI built with the cross-platform Qt Framework. To compile the GUI, Qt 5 is required.
 
 ```bash
-pkg_add qt5
+pkg_add qtbase qttools
 ```
 
 ## Building Bitcoin Core