Fix hashivault_pki_ca docs
A yaml line cannot begin with a ` token.
I'm not sure why this was only revealed when we changed the hyphen in
the last commit.
@@ -111,7 +111,7 @@ options:
default: -1
description:
- Specifies the maximum path length to encode in the generated certificate.
- - `-1` means no limit.
+ - A limit of `-1` means no limit.
- Unless the signing certificate has a maximum path length set, in which case the path length is set
to one less than that of the signing certificate.
- A limit of `0` means a literal path length of zero.
