tools: bpftool: fix plain output and doc for --bpffs option

Edit the documentation of the -f|--bpffs option to make it explicit that
it dumps paths of pinned programs when bpftool is used to list the
programs only, so that users do not believe they will see the name of
the newly pinned program with "bpftool prog pin" or "bpftool prog load".

Also fix the plain output: do not add a blank line after each program
block, in order to remain consistent with what bpftool does when the
option is not passed.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -124,7 +124,8 @@ OPTIONS
 		  Generate human-readable JSON output. Implies **-j**.
 
 	-f, --bpffs
-		  Show file names of pinned programs.
+		  When showing BPF programs, show file names of pinned
+		  programs.
 
 EXAMPLES
 ========

tools/bpf/bpftool/prog.c

@@ -357,10 +357,9 @@ static void print_prog_plain(struct bpf_prog_info *info, int fd)
 	if (!hash_empty(prog_table.table)) {
 		struct pinned_obj *obj;
 
-		printf("\n");
 		hash_for_each_possible(prog_table.table, obj, hash, info->id) {
 			if (obj->id == info->id)
-				printf("\tpinned %s\n", obj->path);
+				printf("\n\tpinned %s", obj->path);
 		}
 	}