*: always backquote stdin, stdout and stderr (#9584)

pages/common/secrethub.md

@@ -3,7 +3,7 @@
 > A tool to keep secrets out of config files.
 > More information: <https://secrethub.io>.
 
-- Print a secret to stdout:
+- Print a secret to `stdout`:
 
 `secrethub read {{path/to/secret}}`
 
@@ -15,7 +15,7 @@
 
 `secrethub write --clip {{path/to/secret}}`
 
-- Store a value supplied on stdin as a new or updated secret:
+- Store a value supplied on `stdin` as a new or updated secret:
 
 `echo "{{secret_value}}" | secrethub write {{path/to/secret}}`