Add a comment to MinimizeTermConstruction describing what it does (#4124

)

Fixes #4113 

This just adds a small comment to describe what
`MinimizeTermConstruction` does as otherwise there's nothing that
explains what it's doing.

Co-authored-by: rv-jenkins <admin@runtimeverification.com>

kernel/src/main/java/org/kframework/compile/MinimizeTermConstruction.java

@@ -17,6 +17,14 @@
 import org.kframework.definition.Sentence;
 import org.kframework.kore.*;
 
+/**
+ * MinimizeTermConstruction.
+ *
+ * <p>Looks for places where #as patterns can be used to reduce the number of constructors in
+ * rewrites:
+ *
+ * <p>`P1 => P2[P1]` -> `P1 #as X => P2[X]`
+ */
 public class MinimizeTermConstruction {
 
   private final Set<KVariable> vars = new HashSet<>();