emacs.pkgs.telega: Prefer telega from melpa stable

Telega uploads packages that are incompatible with stable tdlib
releases to melpa and ones that are compatible to melpa stable.

This makes the melpa packages very unreliable and we should prefer the
one from melpa stable.

pkgs/top-level/emacs-packages.nix

@@ -77,5 +77,14 @@ in makeScope pkgs'.newScope (self: makeOverridable ({
 
     emacsWithPackages = emacsWithPackages { inherit pkgs lib; } self;
     withPackages = emacsWithPackages { inherit pkgs lib; } self;
+
+  }// {
+
+    # Package specific priority overrides goes here
+
+    # Telega uploads packages incompatible with stable tdlib to melpa
+    # Prefer the one from melpa stable
+    inherit (melpaStablePackages) telega;
+
   })
 ) {})