Merge #337: Remove setting link to developer documentation

de30070 qml: remove setting link to developer documentation (jarolrod)

Pull request description:

  We already point to the source code to the official bitcoincore website and the source code in the `About` page. Additionally, this points to bitcoin.org, which we probably don't want to point to.

  [![Windows](https://img.shields.io/badge/OS-Windows-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/win64/unsecure_win_gui.zip?branch=pull/337)
  [![Intel macOS](https://img.shields.io/badge/OS-Intel%20macOS-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/macos/unsecure_mac_gui.zip?branch=pull/337)
  [![Apple Silicon macOS](https://img.shields.io/badge/OS-Apple%20Silicon%20macOS-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/macos_arm64/unsecure_mac_arm64_gui.zip?branch=pull/337)
  [![ARM64 Android](https://img.shields.io/badge/OS-Android-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/android/unsecure_android_apk.zip?branch=pull/337)
  [![ARM32 Android](https://img.shields.io/badge/OS-Android%2032bit-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/android32/unsecure_android_32bit_apk.zip?branch=pull/337)

ACKs for top commit:
  johnny9:
    ACK de30070

Tree-SHA512: ab9b9a9aa396a47899912b93f7262f74777ca90712ea7f9e143fe25670a89d05a9f1903b9c2f7c5410fe9b1063356f05a670412da8baaa4f1320c0454a590b39

Author: hebasto

src/qml/components/DeveloperOptions.qml

@@ -9,20 +9,6 @@ import "../controls"
 
 ColumnLayout {
     spacing: 4
-    Setting {
-        id: devDocsLink
-        Layout.fillWidth: true
-        header: qsTr("Developer documentation")
-        actionItem: ExternalLink {
-            parentState: devDocsLink.state
-            iconSource: "qrc:/icons/export"
-            iconWidth: 30
-            iconHeight: 30
-            link: "https://bitcoin.org/en/bitcoin-core/contribute/documentation"
-        }
-        onClicked: loadedItem.clicked()
-    }
-    Separator { Layout.fillWidth: true }
     Setting {
         id: dbcacheSetting
         Layout.fillWidth: true