where\last is replaced with lastOrDefault
getAstAtPosition is replaced with findToken

Conflicts:
	src/services/pullLanguageService.ts
remove redundant calls to synchronizeHostData, Now synchronization happenes once for every call to LS

Conflicts:
	src/services/compilerState.ts
	tests/cases/unittests/ls/documentRegistry.ts
removed redundant synchronization calls
updated getTypeInfoEligiblePath to accept SourceUnitSyntax instead of filename

Conflicts:
	src/services/pullLanguageService.ts
addressed CR feedback
resolved merge conflicts