treewide: pkgs.pkgconfig -> pkgs.pkg-config, move pkgconfig to alias.nix

continuation of #109595

pkgconfig was aliased in 2018, however, it remained in
all-packages.nix due to its wide usage. This cleans
up the remaining references to pkgs.pkgsconfig and
moves the entry to aliases.nix.

python3Packages.pkgconfig remained unchanged because
it's the canonical name of the upstream package
on pypi.

pkgs/applications/science/math/R/default.nix

@@ -1,6 +1,6 @@
 { lib, stdenv, fetchurl, bzip2, gfortran, libX11, libXmu, libXt, libjpeg, libpng
 , libtiff, ncurses, pango, pcre2, perl, readline, tcl, texLive, tk, xz, zlib
-, less, texinfo, graphviz, icu, pkgconfig, bison, imake, which, jdk, blas, lapack
+, less, texinfo, graphviz, icu, pkg-config, bison, imake, which, jdk, blas, lapack
 , curl, Cocoa, Foundation, libobjc, libcxx, tzdata, fetchpatch
 , withRecommendedPackages ? true
 , enableStrictBarrier ? false
@@ -24,7 +24,7 @@ stdenv.mkDerivation rec {
   buildInputs = [
     bzip2 gfortran libX11 libXmu libXt libXt libjpeg libpng libtiff ncurses
     pango pcre2 perl readline texLive xz zlib less texinfo graphviz icu
-    pkgconfig bison imake which blas lapack curl tcl tk jdk
+    pkg-config bison imake which blas lapack curl tcl tk jdk
   ] ++ lib.optionals stdenv.isDarwin [ Cocoa Foundation libobjc libcxx ];
 
   patches = [