test: update hasFipsCrypto in test/common/README

PR-URL: #28507
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

test/common/README.md

@@ -194,7 +194,12 @@ Indicates whether OpenSSL is available.
 ### hasFipsCrypto
 * [<boolean>]
 
-Indicates `hasCrypto` and `crypto` with fips.
+Indicates that Node.js has been linked with a FIPS compatible OpenSSL library,
+and that FIPS as been enabled using `--enable-fips`.
+
+To only detect if the OpenSSL library is FIPS compatible, regardless if it has
+been enabled or not, then `process.config.variables.openssl_is_fips` can be
+used to determine that situation.
 
 ### hasIntl
 * [<boolean>]