ICU-23359 Reword comment: 'cloned from entry' → 'cloned from input'

Author: hirorogo

icu4c/source/i18n/transreg.h

@@ -105,7 +105,7 @@ class TransliteratorAlias : public UMemory {
     //    Here ID is the ID, aliasID is the idBlock, trans is the
     //    contained RBT, and idSplitPoint is the offset in aliasID
     //    where the contained RBT goes.  compoundFilter is the
-    //    compound filter, and it is owned (cloned from entry).
+    //    compound filter, and it is owned (cloned from input).
     // 3. Rules
     //    Here ID is the ID, aliasID is the rules string.
     //    idSplitPoint is the UTransDirection.