Also makes the style guide explicitly comment on void, but this was the
intent IIRC because it matches Carbon's `-> ()` (and "always" versus
"except for void", which we definitely went back and forth on).
Includes adjusting function pointers, which I definitely forget this
syntax works sometimes.
Excludes utils/tree_sitter/src/scanner.c because it claims to be C, but
really we should probably fix that to be cpp.
This adds a RawStringOstream. Versus TestRawOstream, which is
consolidated over to RawStringOstream, it uses a string for storage
instead of a vector, mainly to support move-to-string semantics. Versus
llvm::raw_string_ostream, it owns the string and supports pwrite (which
is needed for driver and its fd_ostream compatibility requirement).
This converts most uses of llvm::raw_string_ostream, leaving behind a
few in InstNamer that explicitly cannot own the string, such as:
```
llvm::raw_string_ostream(name)
<< "_" << tree.tokens().GetColumnNumber(token);
```
I have this as its own library so that it can use CHECK.
Yes this doesn't save much code, but it's code we repeatedly write.
---------
Co-authored-by: Geoff Romer <gromer@google.com>
Jon Ross-Perkins
