Fix the string resource used to indicate MHTML save type

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 3c88529d26a6e52946a9bcd1df16a9dd627ed7f9..c77cc22fa65acac52fba3eae7468e248b82af952 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -11481,8 +11481,8 @@ The following application will be launched if you accept this request:
       <message name="IDS_SAVE_PAGE_DESC_HTML_ONLY" desc="In the Save Page dialog, the description of saving only the HTML of a webpage.">
         Webpage, HTML Only
       </message>
-      <message name="IDS_SAVE_PAGE_DESC_SINGLE_FILE" desc="In the Save Page dialog, the description of saving both the HTML and all shown resources into an archive.">
-        Web Archive, Single File
+      <message name="IDS_SAVE_PAGE_DESC_SINGLE_FILE" desc="In the Save Page dialog, the description of saving both the HTML and all shown resources into a single file.">
+        Webpage, Single File
       </message>
       <message name="IDS_SAVE_PAGE_DESC_COMPLETE" desc="In the Save Page dialog, the description of saving both the HTML and all shown resources.">
         Webpage, Complete