solar_system, update manual with keyboard controls

update manual with keyboard controls
improve a bit the text

update Authors info

src/activities/solar_system/ActivityInfo.qml

@@ -31,11 +31,17 @@ ActivityInfo {
   description: qsTr("Answer the questions with a correctness of 100%.")
   //intro: "Answer the questions presented and get a 100% correctness among the options."
   //: Help goal
-  goal: qsTr("Learn information about the solar system. If you want to learn more about astronomy, try downloading KStars (https://edu.kde.org/kstars/) or Stellarium (https://stellarium.org/) which are open source astronomy softwares.")
+  goal: qsTr("Learn information about the solar system. If you want to learn more about astronomy, try downloading KStars (https://edu.kde.org/kstars/) or Stellarium (https://stellarium.org/) which are astronomy Free Software.")
   //: Help prerequisite
   prerequisite: ""
   //: Help manual
-  manual: qsTr("Click on a planet or the Sun to reveal questions. Each question contains 4 options. One of those is 100% correct. Try to answer the questions until you get a 100% closeness in the closeness meter.")
+  manual: qsTr("Click on a planet or on the Sun, and answer the corresponding questions. Each question contains 4 options. One of those is 100% correct. Try to answer the questions until you get 100% in the closeness meter.") + ("<br><br>") +
+          qsTr("<b>Keyboard controls:</b>") + ("<br>") +
+          qsTr("-Use Arrow keys to navigate") + ("<br>") +
+          qsTr("-Use Space or Enter key to select") + ("<br>") +
+          qsTr("-Use Escape key to return to previous screen") + ("<br>") +
+          qsTr("-Use Tab key when the hint icon is visible to open it")
+
   credit: ""
   section: "sciences experiment"
   createdInVersion: 9500

src/activities/solar_system/SolarSystem.qml

@@ -4,6 +4,7 @@
  *
  * Authors:
  *    Aman Kumar Gupta <gupta2140@gmail.com>
+ *    Timothée Giet <animtim@gmail.com> (graphics, layout and keyboard controls)
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by