tools: bpftool: fix short option name for printing version in man pages

Manual pages would tell that option "-v" (lower case) would print the
version number for bpftool. This is wrong: the short name of the option
is "-V" (upper case). Fix the documentation accordingly.

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

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

@@ -99,7 +99,7 @@ OPTIONS
 	-h, --help
 		  Print short generic help message (similar to **bpftool help**).
 
-	-v, --version
+	-V, --version
 		  Print version number (similar to **bpftool version**).
 
 	-j, --json