[Docs] Fix formatting errors in migrated content

NOTRY=true
NOPRESUBMIT=true
R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1373223003

Cr-Commit-Position: refs/heads/master@{#31001}

docs/building_with_gyp.md

-<font color='darkred'><b>Build issues? File a bug at code.google.com/p/v8/issues or ask for help on v8-users@googlegroups.com.</b></font>
+**Build issues? File a bug at code.google.com/p/v8/issues or ask for help on v8-users@googlegroups.com.**
 
 # Building V8
 
@@ -211,7 +211,7 @@ build/gyp_v8
 
 #### Custom build settings
 
-See the "custom build settings" section for [Xcode](#Xcode.md) above.
+See the "custom build settings" section for [Xcode](#Xcode) above.
 
 
 #### Running tests