Continuing on #3070.
I moved ParseTree::Node to just Parse::Node, versus Parse::Tree::Node.
Other name changes are just removing "Parse" or "Parser" prefixes.
In EnumBase, I'm directly defining operator<< because the ostream.h
approach just isn't working, not for either of Parse::State nor
Parse::NodeKind. Errors look like:
```toolchain/parser/parser_context.cpp:449:34: error: invalid operands to binary expression ('llvm::raw_ostream' and 'const Carbon::Parse::State')
output << "\t" << i << ".\t" << entry.state;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~
```
The expected template in `Carbon::` is not in the error list; I only see
the:
```
./common/ostream.h:112:6: note: candidate template ignored: requirement 'std::is_base_of_v<std::ostream, llvm::raw_ostream>' was not satisfied [with S = llvm::raw_ostream, T = Carbon::Parse::State]
auto operator<<(S& standard_out, const T& value) -> S& {
^
```
I'm still prodding at this, but not seeing an obvious fix.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Add a language server for carbon as part of GSoC.
This currently does code outline using toolchain parser.
See development steps in utils/vscode/README.md for running and using
language server.