Fix exp_short_init_compact_seq() signature (#2103)

Author: DavisVaughan

NEWS.md

@@ -1,5 +1,7 @@
 # vctrs (development version)
 
+* Fixed the C level signature for the `exp_short_init_compact_seq()` callable.
+
 * Experimental "partial" type support has been removed. This idea never panned out and was not widely used. The following functions have been removed (#2101):
 
   * `is_partial()`

src/init.c

@@ -187,7 +187,7 @@ extern SEXP exp_vec_slice_impl(SEXP, SEXP);
 extern SEXP exp_vec_names(SEXP);
 extern SEXP exp_vec_set_names(SEXP, SEXP);
 extern SEXP exp_short_compact_seq(R_len_t, R_len_t, bool);
-extern SEXP exp_short_init_compact_seq(int*, R_len_t, R_len_t, bool);
+extern void exp_short_init_compact_seq(int*, R_len_t, R_len_t, bool);
 
 // Defined below
 SEXP vctrs_init_library(SEXP);