Merge #18108: Fix .gitignore policy in build_msvc directory

dcb7af053d Ignore only auto-generated .vcxproj files (Hennadii Stepanov)
79c811ca2b Specify ignored bitcoin-qt file precisely (Hennadii Stepanov)

Pull request description:

  This PR makes `git` to ignore only auto-generated `.vcxproj` files, i.e.:
  https://github.com/bitcoin/bitcoin/blob/4c2578706c70148fc001f42a0918a2fb10252b43/build_msvc/msvc-autogen.py#L14-L25

  Fix #17287

ACKs for top commit:
  sipsorcery:
    ACK dcb7af053d.

Tree-SHA512: 5acfc3cb50e1239655bc9715711c8a0489093ed7cc287756614740f67908f11a55976cec75b29e263d4d3579b6b8af99bb3823515d43adf204cd5935fb2e1a3f

.gitignore

@@ -90,7 +90,7 @@ src/qt/bitcoin-qt.includes
 *.qm
 Makefile
 !depends/Makefile
-bitcoin-qt
+src/qt/bitcoin-qt
 Bitcoin-Qt.app
 background.tiff*