docs: cleanup header levels in backend docs (#5698)

docs/content/hdfs.md

@@ -10,6 +10,8 @@ distributed file-system, part of the [Apache Hadoop](https://hadoop.apache.org/)
 
 Paths are specified as `remote:` or `remote:path/to/dir`.
 
+## Configuration
+
 Here is an example of how to make a remote called `remote`. First run:
 
      rclone config
@@ -146,11 +148,6 @@ the following characters are also replaced:
 
 Invalid UTF-8 bytes will also be [replaced](/overview/#invalid-utf8).
 
-### Limitations
-
-- No server-side `Move` or `DirMove`.
-- Checksums not implemented.
-
 {{< rem autogenerated options start" - DO NOT EDIT - instead edit fs.RegInfo in backend/hdfs/hdfs.go then run make backenddocs" >}}
 ### Standard Options
 
@@ -228,3 +225,8 @@ See: the [encoding section in the overview](/overview/#encoding) for more info.
 - Default:     Slash,Colon,Del,Ctl,InvalidUtf8,Dot
 
 {{< rem autogenerated options stop >}}
+
+## Limitations
+
+- No server-side `Move` or `DirMove`.
+- Checksums not implemented.