analyze: always recommend saving the output to a file

The command will refuse to write to a TTY, so give a strong hint
that redirecting to a file is recommended. This makes the synopsis,
man page text, and --help output consistent.

Also drop the space after the redirection operator everywhere.

src/analyze/analyze.c

@@ -240,7 +240,7 @@ static int help(int argc, char *argv[], void *userdata) {
                "  fdstore SERVICE...         Show file descriptor store contents of service\n"
                "  image-policy POLICY...     Analyze image policy string\n"
                "  pcrs [PCR...]              Show TPM2 PCRs and their names\n"
-               "  srk > FILE                 Write TPM2 SRK to stdout\n"
+               "  srk [>FILE]                Write TPM2 SRK (to FILE)\n"
                "\nOptions:\n"
                "     --recursive-errors=MODE Control which units are verified\n"
                "     --offline=BOOL          Perform a security review on unit file(s)\n"