Revise Siren documentation (#6553)

* revise Siren doc

* Fix broken links

* Fix broken links

* broken links

* mdlint

* mdlint

* mdlint again

* Merge branch 'unstable' into book-siren

* test whether I have the required privs :-)

* revise

* some minor siren related changes for the book

* updates re: `--net=host`

* lint

* Minor revision

* Add note

* mdlint

* Merge branch 'unstable' into book-siren

* Merge branch 'unstable' into book-siren

* Merge remote-tracking branch 'origin/unstable' into book-siren

* Fix spellcheck

* Capital letters SSL

book/src/api-vc-auth-header.md

@@ -20,11 +20,11 @@ Authorization: Bearer hGut6B8uEujufDXSmZsT0thnxvdvKFBvh
 The API token is stored as a file in the `validators` directory. For most users
 this is `~/.lighthouse/{network}/validators/api-token.txt`, unless overridden using the
 `--http-token-path` CLI parameter. Here's an
-example using the `cat` command to print the token to the terminal, but any
+example using the `cat` command to print the token for mainnet to the terminal, but any
 text editor will suffice:
 
 ```bash
-cat api-token.txt
+cat ~/.lighthouse/mainnet/validators/api-token.txt
 hGut6B8uEujufDXSmZsT0thnxvdvKFBvh
 ```