Reduce string allocation from TextFactory

Add filters for keywords and snippets.

Fixes #14528

Share common logic in indentation.

use new language property of compilation/parseoption to find out which type it is

added Language property to ParseOption and CompilationOption

Fixed null exception for solution which has both C#/VB and typescript/javascript

Print out more information about why a test failed.

property name followed the compiler code base pattern.

Provide user facing options to control if expression bodied members are preferred or not.

Rollback any document changes if adding a nuget package fails.

allow SourceText From TextReader to have null encoding lke the  one from string.

track session across remote host

Enables CreateTupleTypeSymbol_UnderlyingTypeIsError test for VB

guard session against ObjectDisposedException from StreamJsonRpc.