rename posterg → xamxam throughout: nginx conf, scripts, PHP source, docs

nginx/docs/HTACCESS_TO_NGINX.md

@@ -4,11 +4,11 @@
 > directives that nginx **silently ignores**. None of the rules were active
 > in production.
 
-> **Status:** Migrated into `nginx/posterg.conf`
+> **Status:** Migrated into `nginx/xamxam.conf`
 
 ---
 
-## Rules migrated into `nginx/posterg.conf`
+## Rules migrated into `nginx/xamxam.conf`
 
 | Apache `.htaccess` rule | nginx equivalent | Location |
 |---|---|---|