docs: move SGLang and vLLM Prometheus metrics documentation to docs path (#3677)

Signed-off-by: Keiven Chang <keivenchang@users.noreply.github.com>

docs/backends/sglang/prometheus.md

@@ -10,7 +10,7 @@ When running SGLang through Dynamo, SGLang engine metrics are automatically pass
 
 For the complete and authoritative list of all SGLang metrics, always refer to the official documentation linked above.
 
-Dynamo runtime metrics are documented in [docs/guides/metrics.md](../../../docs/guides/metrics.md).
+Dynamo runtime metrics are documented in [docs/guides/metrics.md](../../guides/metrics.md).
 
 ## Metric Reference
 

docs/backends/vllm/prometheus.md

@@ -10,7 +10,7 @@ When running vLLM through Dynamo, vLLM engine metrics are automatically passed t
 
 For the complete and authoritative list of all vLLM metrics, always refer to the official documentation linked above.
 
-Dynamo runtime metrics are documented in [docs/guides/metrics.md](../../../docs/guides/metrics.md).
+Dynamo runtime metrics are documented in [docs/guides/metrics.md](../../guides/metrics.md).
 
 ## Metric Reference
 

docs/hidden_toctree.rst

@@ -60,6 +60,7 @@
    backends/sglang/multimodal_epd.md
    backends/sglang/sgl-hicache-example.md
    backends/sglang/sglang-disaggregation.md
+   backends/sglang/prometheus.md
 
    examples/README.md
    examples/runtime/hello_world/README.md
@@ -70,6 +71,7 @@
    backends/vllm/deepseek-r1.md
    backends/vllm/gpt-oss.md
    backends/vllm/multi-node.md
+   backends/vllm/prometheus.md
 
 
 ..   TODO: architecture/distributed_runtime.md and architecture/dynamo_flow.md