Auto merge of servo#27998 - simonschmeisser:patch-2, r=jdm

add instruction for building libsimpleservo

fixes servo#27995

---
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ports/libsimpleservo/README.md

@@ -1,3 +1,11 @@
+# libsimpleservo
 This is a basic wrapper around Servo. While libservo itself (/components/servo/) offers a lot of flexibility,
 libsimpleservo (/ports/libsimpleservo/) tries to make it easier to embed Servo, without much configuration needed.
 It is limited to only one view (no tabs, no multiple rendering area).
+
+## Building
+Run the following command to generate `libsimpleservo`
+```
+./mach build --release --libsimpleservo
+```
+this will generate a shared library (`libsimpleservo.so` on linux) as well as a header file in `target/release` that you can then link to your application.