int2enum is not recognized as keyword/predefined function
## Summary
int2enum is not recognized as keyword/predefined function
## Steps and/or TTCN-3 code to reproduce
write a code containing `int2enum`
## What is the current bug behavior?
it is not highlighted by the editor like the other predefined functions
## What is the expected correct behavior?
it should be highlighted like the other predefined functions
## Titan version
8.3.0
## Platform details (OS type and version)
All
/cc @aknappqwt @mmagyari
issue