[Docs] Add a start tag to build.inc.md (#26747)

Signed-off-by: windsonsea <haifeng.yao@daocloud.io>

docs/getting_started/installation/cpu/arm.inc.md

@@ -23,7 +23,7 @@ ARM CPU backend currently supports Float32, FP16 and BFloat16 datatypes.
 # --8<-- [end:pre-built-wheels]
 # --8<-- [start:build-wheel-from-source]
 
---8<-- "docs/getting_started/installation/cpu/build.inc.md"
+--8<-- "docs/getting_started/installation/cpu/build.inc.md:extra-information"
 
 Testing has been conducted on AWS Graviton3 instances for compatibility.
 

docs/getting_started/installation/cpu/build.inc.md

+# --8<-- [start:extra-information]
+
 First, install the recommended compiler. We recommend using `gcc/g++ >= 12.3.0` as the default compiler to avoid potential problems. For example, on Ubuntu 22.4, you can run:
 
 ```bash
@@ -39,7 +41,4 @@ If you want to develop vLLM, install it in editable mode instead.
 VLLM_TARGET_DEVICE=cpu python setup.py develop
 ```
 
-!!! note
-    If you are building vLLM from source and not using the pre-built images, remember to set `LD_PRELOAD="/usr/lib/x86_64-linux-gnu/libtcmalloc_minimal.so.4:$LD_PRELOAD"` on x86 machines before running vLLM.
-
 # --8<-- [end:extra-information]