missing description for FontMetricFlags

rearrange class descriptions to make them
appear consistently inside the #Class
declaration in the .bmh files.

Look for the descriptions there and
regenerate the .md files.

Docs-Preview: https://skia.org/?cl=46523
TBR=caryclark@google.com
Bug: skia: 6898
Change-Id: I00a176428725ef27667d3f23d76d6b7ff0cfced1
Reviewed-on: https://skia-review.googlesource.com/46523
Commit-Queue: Cary Clark <caryclark@google.com>
Reviewed-by: Cary Clark <caryclark@skia.org>
diff --git a/docs/SkPixmap_Reference.bmh b/docs/SkPixmap_Reference.bmh
index 83f3502..409090b 100644
--- a/docs/SkPixmap_Reference.bmh
+++ b/docs/SkPixmap_Reference.bmh
@@ -1,5 +1,6 @@
 #Topic Pixmap
- 
+#Alias Pixmap_Reference
+
 #Class SkPixmap
 
 Pixmap provides a utility to pair SkImageInfo with pixels and row bytes.