chore: add to CHANGELOG

Author: arielherself

CHANGELOG.md

@@ -185,6 +185,30 @@
 - The compiler will not generate needless code for unused pattern variables.
   ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
 
+- The compiler will now emit a warning when a function definition shadows
+  an imported function with the same name.
+
+```gleam
+import module.{fun}
+
+fn fun() {}
+```
+
+Will produce the following warning:
+
+```
+warning: Definition of "fun" shadows an imported value
+  ┌─ /src/main.gleam:3:4
+  │
+3 │ fn fun() {}
+  │    ^^^
+
+The imported value could not be used anyway.
+Hint: You could remove the imported value.
+```
+
+([Ariel Parker](https://github.com/arielherself))
+
 ### Build tool
 
 - The build tool now supports placing modules in a directory called `dev`,