Add detection for SWAG nginx proxy confs (#4036)

* Add detection for SWAG nginx proxy confs

These nginx config files have the format "appname.subdomain.conf" or "appname.subfolder.conf"

* Excape dot in regex

Co-authored-by: Mikko <Andriamanitra@users.noreply.github.com>

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Co-authored-by: Mikko <Andriamanitra@users.noreply.github.com>

Author: KWottrich

runtime/syntax/nginx.yaml

@@ -1,7 +1,7 @@
 filetype: nginx
 
 detect:
-    filename: "nginx.*\\.conf$|\\.nginx$"
+    filename: "nginx.*\\.conf$|\\.nginx$|\\.sub(domain|folder)\\.conf$"
     header: "^(server|upstream)[a-z ]*\\{$"
 
 rules: