updated usage example (#9081)

* updated usage example

* Docs: updated examples with base64 - removed herestring for echo instead that's more simple.

* Docs: updated examples with base64 - removed herestring for echo instead that's more simple.

Co-authored-by: Mehdi Ahmadi <aphorise@gmail.com>

changelog/9081.txt

@@ -0,0 +1,4 @@
+
+```release-note:improvement
+website/docs: changed to echo for all string examples instead of (<<<) here-string.
+```

website/content/api-docs/secret/transit.mdx

@@ -577,7 +577,7 @@ mechanism for this data as part of a JSON payload is to base64-encode it.
 Fist, encode the plaintext with base64:
 
 ```shell-session
-$ base64 <<< "the quick brown fox"
+$ echo "the quick brown fox" | base64
 dGhlIHF1aWNrIGJyb3duIGZveAo=
 ```
 

website/content/docs/secrets/consul.mdx

@@ -131,7 +131,7 @@ management tool.
         Write a policy and proceed to link it to the role:
 
         ```shell-session
-        $ vault write consul/roles/my-role policy="$(base64 <<< 'key "" { policy = "read" }')"
+        $ vault write consul/roles/my-role policy="$(echo 'key "" { policy = "read" }' | base64)"
         Success! Data written to: consul/roles/my-role
         ```
 

website/content/docs/secrets/transit/index.mdx

@@ -155,7 +155,7 @@ the proper permission, it can use this secrets engine.
     mechanism for this data as part of a JSON payload is to base64-encode it.
 
     ```text
-    $ vault write transit/encrypt/my-key plaintext=$(base64 <<< "my secret data")
+    $ vault write transit/encrypt/my-key plaintext=$(echo "my secret data" | base64)
 
     Key           Value
     ---           -----