Add dev-qt from an older version of the gentoo repo

Qt5 has been removed, we restore it since we still use it.

dev-qt/qtlanguageserver/qtlanguageserver-6.8.3.ebuild

@@ -0,0 +1,15 @@
+# Copyright 2024-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit qt6-build
+
+DESCRIPTION="Implementation of the Language Server Protocol for Qt"
+
+if [[ ${QT6_BUILD_TYPE} == release ]]; then
+	KEYWORDS="amd64"
+fi
+
+RDEPEND="~dev-qt/qtbase-${PV}:6"
+DEPEND="${RDEPEND}"