Fix MSVC warning about 2147483648 not fitting in an int

This also cleans up some of the documentation. I'm not sure what happened to that last line.

BUG=webm:1501

Change-Id: Ie0ff0607ebb60d033e7ad40bdc7943c0a6bd6783
diff --git a/webm_parser/include/webm/status.h b/webm_parser/include/webm/status.h
index 52abd38..ff3f0c6 100644
--- a/webm_parser/include/webm/status.h
+++ b/webm_parser/include/webm/status.h
@@ -95,9 +95,10 @@
     // The following codes are internal-only and should not be used by users.
     // Additionally, these codes should never be returned to the user; doing so
     // is considered a bug.
-    // Parsing should switch from reading to skipping elements (internal-only
-    // use; .
-    kSwitchToSkip = -2147483648,
+    /**
+     \internal Parsing should switch from reading to skipping elements.
+     */
+    kSwitchToSkip = INT32_MIN,
   };
 
   /**