rename DSL documentation for clarity (#2851) (#2852)

(cherry picked from commit 4ef7740)

Co-authored-by: Miguel Grinberg <[email protected]>

Author: github-actions[bot]

docs/reference/_configuration.md renamed to docs/reference/dsl_configuration.md

@@ -12,8 +12,8 @@ toc:
   - file: examples.md
   - file: elasticsearch-dsl.md
     children:
-      - file: _configuration.md
-      - file: _tutorials.md
-      - file: _how_to_guides.md
-      - file: _examples.md
-  - file: client-helpers.md
+      - file: dsl_configuration.md
+      - file: dsl_tutorials.md
+      - file: dsl_how_to_guides.md
+      - file: dsl_examples.md
+  - file: client-helpers.md