libtextstyle: Use #include <...> style for system headers.
* libtextstyle/gnulib-local/lib/libcroco/cr-additional-sel.c: Use #include <...>
style for system headers.
* libtextstyle/gnulib-local/lib/libcroco/cr-input.c: Likewise.
* libtextstyle/gnulib-local/lib/libcroco/cr-num.c: Likewise.
* libtextstyle/gnulib-local/lib/libcroco/cr-parser.c: Likewise.
* libtextstyle/gnulib-local/lib/libcroco/cr-stylesheet.c: Likewise.
* libtextstyle/gnulib-local/lib/libcroco/cr-tknzr.c: Likewise.
