PDB: Added description of the type info stream references
PDB: Added description of the type info stream references

BUG=
R=manzagop@chromium.org, siggi@chromium.org

Review URL: https://codereview.chromium.org/1329433002.

Eloston/syzygy,google/syzygy,supriyantomaftuh/syzygy,google/syzygy,supriyantomaftuh/syzygy,supriyantomaftuh/syzygy,google/syzygy,google/syzygy,supriyantomaftuh/syzygy,Eloston/syzygy