only-en pick-24 pick-25 unify placeholder names

Author: eseyffarth

src/common/en/agent_linux.asciidoc

@@ -571,7 +571,7 @@ Here, with `root` privileges, make a request to the {CMK} xref:glossar#site[site
 ----
 {c-root} cmk-agent-ctl register \
              --hostname mynewhost \
-             --server cmkserver \
+             --server mycmkserver \
              --site mysite \
              --user agent_registration \
              --password 'PTEGDYXBFXVGNDPRL'
@@ -588,7 +588,7 @@ For clarity here, we have abbreviated the server certificate to be confirmed:
 
 [{shell}]
 ----
-Attempting to register at cmkserver:8000/mysite. Server certificate details:
+Attempting to register at mycmkserver:8000/mysite. Server certificate details:
 
 PEM-encoded certificate:
 ---BEGIN CERTIFICATE---
@@ -642,7 +642,7 @@ The command line call presented here is therefore primarily for testing and debu
 [{shell}]
 ----
 {c-root} cmk-agent-ctl register-new \
-             --server cmkserver \
+             --server mycmkserver \
              --site mysite \
              --agent-labels testhost:true \
              --user agent_registration \
@@ -712,7 +712,7 @@ We redirect the JSON output to a file in the example:
 ----
 {c-root} cmk-agent-ctl proxy-register \
     --hostname mynewhost3 \
-    --server cmkserver \
+    --server mycmkserver \
     --site mysite \
     --user agent_registration > /tmp/mynewhost3.json
 ----
@@ -730,7 +730,7 @@ This process is also possible in a single step using a pipeline where the output
 ----
 {c-root} cmk-agent-ctl proxy-register \
              --hostname mynewhost3 \
-             --server cmkserver \
+             --server mycmkserver \
              --site mysite \
              --user agent_registration \
              --password 'PTEGDYXBFXVGNDPRL' | \