Update documentation links to https://gdevic.github.io/Z80Explorer

Author: gdevic

README.md

@@ -3,7 +3,7 @@ Visual Zilog Z80 netlist-level simulator
 
 Z80 Explorer is a Zilog Z80 netlist-level simulator capable of running Z80 machine code and an educational tool with features that help reverse engineer and understand this chip better.
 
-Application's User's Guide: [Users Guide](Z80Explorer.pdf)
+Application's User's Guide: [Users Guide](https://gdevic.github.io/Z80Explorer)
 <br>
 It is also described in a blog: https://baltazarstudios.com/z80explorer
 <br>

src/MainWindow.ui

@@ -182,7 +182,7 @@
     <string>Open the user's manual online</string>
    </property>
    <property name="whatsThis">
-    <string>https://baltazarstudios.com/uc/Z80ExplorerGuide</string>
+    <string>https://gdevic.github.io/Z80Explorer</string>
    </property>
   </action>
   <action name="actionEditColors">