Added better diagnostics

include/dusk/AST/ASTNode.h

include/dusk/AST/CMakeLists.txt

include/dusk/AST/Decl.h

include/dusk/AST/Diagnostics.h

include/dusk/AST/DiagnosticsParse.h

include/dusk/AST/Expr.h

include/dusk/AST/Pattern.h

include/dusk/AST/Stmt.h

include/dusk/Basic/CMakeLists.txt

include/dusk/Basic/SourceManager.h

include/dusk/Frontend/Compiler.h

include/dusk/Parse/Lexer.h

include/dusk/Parse/Parser.h

lib/AST/ASTWalker.cpp

lib/AST/Decl.cpp

lib/AST/Diagnostics.cpp

lib/AST/Expr.cpp

lib/AST/Pattern.cpp

lib/AST/Stmt.cpp

lib/Frontend/Compiler.cpp