Add sort aliases (#3778)

Author: Drodt

key.core.infflow/src/main/java/de/uka/ilkd/key/informationflow/macros/AbstractFinishAuxiliaryComputationMacro.java

@@ -80,6 +80,9 @@ protected final void mergeNamespaces(Proof initiatingProof, Proof sideProof) {
         mergeNamespace(initiatingProofNS.functions(), sideProofNS.functions());
         mergeNamespace(initiatingProofNS.ruleSets(), sideProofNS.ruleSets());
         mergeNamespace(initiatingProofNS.sorts(), sideProofNS.sorts());
+        mergeNamespace(initiatingProofNS.sortAliases(), sideProofNS.sortAliases());
+        mergeNamespace(initiatingProofNS.parametricSorts(), sideProofNS.parametricSorts());
+        mergeNamespace(initiatingProofNS.parametricFunctions(), sideProofNS.parametricFunctions());
         mergeNamespace(initiatingProofNS.choices(), sideProofNS.choices());
     }
 

key.core/src/main/antlr4/KeYLexer.g4

@@ -78,6 +78,7 @@ PROXY : '\\proxy';
 EXTENDS : '\\extends';
 ONEOF : '\\oneof';
 ABSTRACT : '\\abstract';
+ALIAS: '\\alias';
 
 // Keywords used in schema variable declarations
 SCHEMAVARIABLES : '\\schemaVariables';