texmacs: replace texlive.combined.scheme-small with texliveSmall

pkgs/applications/editors/texmacs/default.nix

···
   guile_1_8, xmodmap, which, freetype,
   libjpeg,
   sqlite,
-  tex ? null,
+  texliveSmall ? null,
   aspell ? null,
   git ? null,
   python3 ? null,
···
   pname = "texmacs";
   version = "2.1.2";
   common = callPackage ./common.nix {
-    inherit tex extraFonts chineseFonts japaneseFonts koreanFonts;
+    inherit extraFonts chineseFonts japaneseFonts koreanFonts;
+    tex = texliveSmall;
   };
 in
 stdenv.mkDerivation {
···
       which
       ghostscriptX
       aspell
-      tex
+      texliveSmall
       git
       python3
     ])

pkgs/top-level/all-packages.nix

···
 
   texmacs = libsForQt5.callPackage ../applications/editors/texmacs {
     stdenv = if stdenv.isDarwin then darwin.apple_sdk_11_0.stdenv else stdenv;
-    tex = texlive.combined.scheme-small;
     extraFonts = true;
   };