Breaks `--trace` into two flags:
- `--parser_debug`, which sets the parser debug level (which I haven't dug into piping with `--trace`, but seemed likely to be troublesome)
- `--trace_file`, which now the type checker and interpreter will use for trace information (note compile errors should use a different channel)
Most of the file edits are just mechanical testdata flag updates: `sed -i 's/--trace/--parser_debug --trace_file=-/' testdata/**/*.carbon`
To explain the output paths:
- parse/compile errors: stderr
- print() calls: stdout
- parser tracing: `--parser_debug` option, stdout (formerly stdout if `--trace`)
- type check/compile tracing: `--trace_file=<file>`, giving `-` uses stdout (formerly stdout if `--trace`)
- return code of executed Carbon code: `--trace_file` if set, stdout if not (formerly stdout always)
* adding methods to the ast
* pre commit stuff?
* implementation of class functions
* implemented methods
* some cleanup
* more cleanup
* add newlines in test programs
* pre-commit fixups
* added include of return_term.h
* a test of a method calling another method
* replacing Member with Declaration
* removing the member.h etc files
* clarify a type annotation
* update uses of FunctionDeclaration
* remove ReturnTarget, no longer needed
* more cleanup
* more cleanup
* yet more cleanup, playing with pre-commit
* did a pre-commit run --all-files
* fixed const issue
* remove comment
* checking dependencies in BUILD files and headers
* pre-commit working now
* refactor NominalClassType to just hold a pointer to the class declaration
* remove Member from rtti
* responding to Geoffreys review
* change field_types to a non-member function