Update src/SUMMARY.md

Co-Authored-By: rajcspsg <raj.cs.psg@gmail.com>

Author: mark-i-m

src/SUMMARY.md

@@ -14,7 +14,7 @@
     - [Adding new tests](./tests/adding.md)
     - [Using `compiletest` + commands to control test execution](./compiletest.md)
 - [Walkthrough: a typical contribution](./walkthrough.md)
-- [Implementing new feature](./implementing_new_feature.md)
+- [Implementing new features](./implementing_new_feature.md)
 - [Stabilizing Features](./stabilization_guide.md)
 - [Debugging the Compiler](./compiler-debugging.md)
 - [Profiling the compiler](./profiling.md)