Add qt5-doc makedepends so that generated QCH files are correctly linked

PKGBUILD

@@ -2,13 +2,13 @@
 
 pkgname=pulseaudio-qt
 pkgver=1.1.0
-pkgrel=1
+pkgrel=2
 pkgdesc='Qt bindings for libpulse'
 arch=(x86_64)
 url='https://community.kde.org/Frameworks'
 license=(LGPL)
 depends=(qt5-base libpulse)
-makedepends=(extra-cmake-modules doxygen qt5-tools)
+makedepends=(extra-cmake-modules doxygen qt5-tools qt5-doc)
 source=("https://download.kde.org/stable/$pkgname/$pkgname-$pkgver.tar.xz"{,.sig})
 sha256sums=('9c7cbc484dee6ab6bd6b479a5cca14c7f38a4d020f03e99ecfd047136da18662'
             'SKIP')
@@ -22,7 +22,6 @@ prepare() {
 build() {
   cd build
   cmake ../$pkgname-$pkgver \
-    -DCMAKE_INSTALL_PREFIX=/usr \
     -DCMAKE_INSTALL_LIBDIR=lib \
     -DBUILD_QCH=ON \
     -DBUILD_TESTING=OFF