Apply suggestions from code review

Co-authored-by: Dominik Menke <[email protected]>

providers/dns/selfhostde/internal/readme.md

@@ -4,4 +4,4 @@ SelfHost doesn't provide an official API documentation and there are no endpoint
 
 ## More
 
-This link (https://kirk.selfhost.de/cgi-bin/selfhost?p=document&name=api) content a PDF that doesn't describe the endpoint used by the client.
+The documentation found at https://kirk.selfhost.de/cgi-bin/selfhost?p=document&name=api (PDF) describes the DynDNS/ddns API endpoint and is not used by our client.

providers/dns/selfhostde/selfhostde.toml

@@ -15,21 +15,27 @@ Additional = """
 SelfHost.de doesn't have an API to create or delete TXT records, there is only an "unofficial" and undocumented endpoint to update an existing TXT record.
 
 So, before using lego to request a certificate for a given domain or wildcard (such as `my.example.org` or `*.my.example.org`),
-you should create:
+you must create:
 - one TXT record named `_acme-challenge.my.example.org` if you are **not** using wildcard for this domain.
 - two TXT records named `_acme-challenge.my.example.org` if you are using wildcard for this domain.
 
 After that you must edit the TXT record(s) to get the ID(s).
 
-You should recreate a mapping to fill the `SELFHOSTDE_RECORDS_MAPPING` environement variable as following:
+You then must prepare the `SELFHOSTDE_RECORDS_MAPPING` environment variable with the following format:
 
 ```
 <domain_A>:<record_id_A1>:<record_id_A2>,<domain_B>:<record_id_B1>:<record_id_B2>,<domain_C>:<record_id_C1>:<record_id_C2>
 ```
 
-Each group of domain + record id(s) is separated with a comma `,`.
+where each group of domain + record ID(s) is separated with a comma (`,`), and the domain and record ID(s) are separated with a colon (`:`).
+
+For example, if you want to create or renew a certificate for `my.example.org`, `*.my.example.org`, and `other.example.org`, you would need:
+
+- two separate records for `_acme-challenge.my.example.org`, and
+- another separate record for `_acme-challenge.other.example.org`.
+
+The resulting environment variable would then be: `SELFHOSTDE_RECORDS_MAPPING=my.example.com:123:456,other.example.com:789`
 
-Each record id is separated with 2 dots `:`.
 """
 
 [Configuration]