kde/{kate,konqueror,okular}: decrease text mimetype preference

These .desktop files set InitialPreference>1 which will override other
associations even the .desktop appears first in XDG_DATA_DIRS. This
applies to:

- org.kde.kate.desktop
- org.kde.kwrite.desktop
- kfmclient_html.desktop
- okularApplication_txt.desktop

Fixes #86137

pkgs/applications/kde/kate.nix

@@ -14,6 +14,16 @@ mkDerivation {
     maintainers = [ lib.maintainers.ttuegel ];
   };
 
+  # InitialPreference values are too high and end up making kate &
+  # kwrite defaults for anything considered text/plain. Resetting to
+  # 1, which is the default.
+  postPatch = ''
+    substituteInPlace kate/data/org.kde.kate.desktop \
+      --replace InitialPreference=9 InitialPreference=1
+    substituteInPlace kwrite/data/org.kde.kwrite.desktop \
+      --replace InitialPreference=8 InitialPreference=1
+  '';
+
   nativeBuildInputs = [ extra-cmake-modules kdoctools ];
   buildInputs = [
     libgit2

pkgs/applications/kde/konqueror.nix

@@ -12,9 +12,17 @@ mkDerivation {
     kdelibs4support kcmutils khtml kdesu
     qtwebkit qtwebengine qtx11extras qtscript qtwayland
   ];
+
+  # InitialPreference values are too high and any text/html ends up
+  # opening konqueror, even if firefox or chromium are also available.
+  # Resetting to 1, which is the default.
+  postPatch = ''
+    substituteInPlace kfmclient_html.desktop \
+      --replace InitialPreference=9 InitialPreference=1
+  '';
+
   meta = {
     license = with lib.licenses; [ gpl2 ];
     maintainers = with lib.maintainers; [ ];
   };
 }
-

pkgs/applications/kde/okular.nix

@@ -18,6 +18,15 @@ mkDerivation {
     kwindowsystem libkexiv2 libspectre libzip phonon poppler qca-qt5
     qtdeclarative qtsvg threadweaver kcrash
   ] ++ lib.optional (!stdenv.isAarch64) chmlib;
+
+  # InitialPreference values are too high and end up making okular
+  # default for anything considered text/plain. Resetting to 1, which
+  # is the default.
+  postPatch = ''
+    substituteInPlace generators/txt/okularApplication_txt.desktop \
+      --replace InitialPreference=3 InitialPreference=1
+  '';
+
   meta = with lib; {
     homepage = "http://www.kde.org";
     license = with licenses; [ gpl2 lgpl21 fdl12 bsd3 ];