clang docs: Be a bit more confident about debug info on Windows.

docs/clang.md

 # Clang
 
 [Clang](http://clang.llvm.org/) is a compiler with many desirable features
 (outlined on their website).
 
 Chrome can be built with Clang. It is now the default compiler on Mac and Linux
 for building Chrome, and it is currently useful for its warning and error
 messages on Android and Windows.
 
 See
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 python tools\clang\scripts\update.py
 # run `gn args` and add `is_clang = true` to your args.gn, then...
 ninja -C out\Debug chrome
 ```
 
 The `update.py` script only needs to be run once per checkout. Clang will be
 kept up to date by `gclient runhooks`.
 
 Current brokenness:
 
-*   Debug info is very limited.
 *   To get colored diagnostics, you need to be running
     [ansicon](https://github.com/adoxa/ansicon/releases).
+*   Debug info does now work, but support for it is new.  If you see something
+    not working right, please file a bug and mark it as blocking the
+    [clang/win debug info tracking bug](https://crbug.com/636111).
 
 ## Using a custom clang binary
 
 These instructions are for GYP which no longer works. Something similar needs
 to be set up for the GN build if you want to do this. For reference, here are
 the old instructions:
 
 If you want to try building Chromium with your own clang binary that you've
 already built, set `make_clang_dir` to the directory containing `bin/clang`
 (i.e. the directory you ran cmake in, or your `Release+Asserts` folder if you
@@ skipping 24 matching lines @@
 
 **Experimental!**
 
 LLD is a relatively new linker from LLVM. The current focus is on Windows and
 Linux support, where it can link Chrome approximately twice as fast as gold and
 MSVC's link.exe as of this writing. LLD does not yet support generating PDB
 files, which makes it hard to debug Chrome while using LLD.
 
 Set `use_lld = true` in args.gn. Currently this configuration is only supported
 on Windows.