bundle API: start writing API documentation

There are no other API docs in bundle.h, but this is at least a
start. We'll add a parameter to this function in a subsequent commit,
but let's start by documenting it.

The "/**" comment (as opposed to "/*") signifies the start of API
documentation. See [1] and bdfdaa4 (strbuf.h: integrate
api-strbuf.txt documentation, 2015-01-16) and 6afbbdd (strbuf.h:
unify documentation comments beginnings, 2015-01-16) for a discussion
of that convention.

1. https://lore.kernel.org/git/[email protected]/

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

bundle.h

@@ -27,6 +27,13 @@ int create_bundle(struct repository *r, const char *path,
 		  int version);
 int verify_bundle(struct repository *r, struct bundle_header *header, int verbose);
 #define BUNDLE_VERBOSE 1
+
+/**
+ * Unbundle after reading the header with read_bundle_header().
+ *
+ * We'll invoke "git index-pack --stdin --fix-thin" for you on the
+ * provided `bundle_fd` from read_bundle_header().
+ */
 int unbundle(struct repository *r, struct bundle_header *header,
 	     int bundle_fd, int flags);
 int list_bundle_refs(struct bundle_header *header,