Fix ServiceTypes, ExcludeServiceTypes, and DocPath desktop file entries to match XDG specifications

diff --git a/src/ktechlab.desktop b/src/ktechlab.desktop
index 08ad96e..a84a39d 100644
--- a/src/ktechlab.desktop
+++ b/src/ktechlab.desktop
@@ -5,7 +5,7 @@
 Exec=ktechlab %i %m -caption "%c"
 Icon=ktechlab
 Type=Application
-DocPath=ktechlab/index.html
+X-DocPath=ktechlab/index.html
 Comment=An IDE for microcontrollers and electronics
 Terminal=0
 MimeType=application/x-ktechlab;application/x-flowcode;application/x-circuit;application/x-microbe;