Document all the cases where HoverInformation fields can be absent.

editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java

Index: editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java
diff --git a/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java
index a9412eafa27a22bf183140f7fc6e604c0de4d080..ef8c5f88e88a07a96789a202f2d15577be80b1c5 100644
--- a/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java
+++ b/editor/tools/plugins/com.google.dart.server/src/com/google/dart/server/generated/types/HoverInformation.java
@@ -57,20 +57,22 @@ public class HoverInformation {
 
   /**
    * The path to the defining compilation unit of the library in which the referenced element is
-   * declared. This data is omitted if there is no referenced element.
+   * declared. This data is omitted if there is no referenced element, or if the element is declared
+   * inside an HTML file.
    */
   private final String containingLibraryPath;
 
   /**
    * The name of the library in which the referenced element is declared. This data is omitted if
-   * there is no referenced element.
+   * there is no referenced element, or if the element is declared inside an HTML file.
    */
   private final String containingLibraryName;
 
   /**
    * The dartdoc associated with the referenced element. Other than the removal of the comment
    * delimiters, including leading asterisks in the case of a block comment, the dartdoc is
-   * unprocessed markdown. This data is omitted if there is no referenced element.
+   * unprocessed markdown. This data is omitted if there is no referenced element, or if the element
+   * has no dartdoc.
    */
   private final String dartdoc;
 
@@ -167,7 +169,7 @@ public class HoverInformation {
 
   /**
    * The name of the library in which the referenced element is declared. This data is omitted if
-   * there is no referenced element.
+   * there is no referenced element, or if the element is declared inside an HTML file.
    */
   public String getContainingLibraryName() {
     return containingLibraryName;
@@ -175,7 +177,8 @@ public class HoverInformation {
 
   /**
    * The path to the defining compilation unit of the library in which the referenced element is
-   * declared. This data is omitted if there is no referenced element.
+   * declared. This data is omitted if there is no referenced element, or if the element is declared
+   * inside an HTML file.
    */
   public String getContainingLibraryPath() {
     return containingLibraryPath;
@@ -184,7 +187,8 @@ public class HoverInformation {
   /**
    * The dartdoc associated with the referenced element. Other than the removal of the comment
    * delimiters, including leading asterisks in the case of a block comment, the dartdoc is
-   * unprocessed markdown. This data is omitted if there is no referenced element.
+   * unprocessed markdown. This data is omitted if there is no referenced element, or if the element
+   * has no dartdoc.
    */
   public String getDartdoc() {
     return dartdoc;