Merge #16534: build: add Qt Creator Makefile.am.user to .gitignore

0a4e4a0 [build] .gitignore add Qt Creator Makefile.am.user (Peter Bushnell)

Pull request description:

  Opening Bitcoin with Qt Creator via the Makefile.am generates a Makefile.am.user. Would be handy to have this file ignored. Looking around I can see this file has snuck into a few downstream projects. I do personally find myself editing commits to remove this file when I've not been paying attention. There's got to have been a few PRs with this file accidentally attached.

ACKs for top commit:
  promag:
    ACK 0a4e4a0.
  practicalswift:
    ACK 0a4e4a0 -- diff looks correct
  fanquake:
    ACK 0a4e4a0 - Something like this might be better in your local .gitignore_global, but we do have a section on Qt Creator in the docs, so I guess this is fine.

Tree-SHA512: 282fd37ec6b313bf86ebe85a42e7f05b14969c683d32f01d2561f4e15d90a2e89f4d0e3c227cb3350684bcae21d178ea343edb32c4c1d33f4849246222c9b8d5

Author: fanquake

.gitignore

@@ -91,6 +91,9 @@ bitcoin-qt
 Bitcoin-Qt.app
 background.tiff*
 
+# Qt Creator
+Makefile.am.user
+
 # Unit-tests
 Makefile.test
 bitcoin-qt_test