python3Packages.hdf5plugin: drop redundant snappy system-library entry

snappy is not a standalone filter; the Blosc filter links the system
c-blosc which already provides it. Enabling "snappy" produced
byte-identical plugin binaries, so the entry was dead.

Assisted-by: claude-code with claude-opus-4-8[1m]-high

pkgs/development/python-modules/hdf5plugin/default.nix

@@ -49,7 +49,6 @@ buildPythonPackage (finalAttrs: {
     bzip2
     charls
     lz4
-    # snappy
     # zfp
     zlib
     zstd
@@ -62,7 +61,6 @@ buildPythonPackage (finalAttrs: {
     "bz2"
     "charls"
     "lz4"
-    # "snappy" # not a standalone filter; provided via the snappy-enabled c-blosc above
     # "sperr" # not packaged?
     # "zfp" #  pkgconfig: (lib)zfp not found
     "zlib"