update docs for paint

Bug: skia:
Change-Id: I3d2938904fcd760c7090c6501f7f935b02206034
Reviewed-on: https://skia-review.googlesource.com/c/193162
Reviewed-by: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
diff --git a/docs/SkPaint_Reference.bmh b/docs/SkPaint_Reference.bmh
index 35b3794..61f5999 100644
--- a/docs/SkPaint_Reference.bmh
+++ b/docs/SkPaint_Reference.bmh
@@ -682,6 +682,17 @@
 
 ##
 
+#Method float getAlphaf() const
+#In Alpha_Methods
+#Line # returns Color_Alpha, color opacity ##
+#Populate
+
+#Example
+    SkPaint paint;
+##
+
+##
+
 #Method void setAlpha(U8CPU a)
 #In Alpha_Methods
 #Line # sets Color_Alpha, color opacity ##
@@ -700,6 +711,17 @@
 
 ##
 
+#Method void setAlphaf(float a)
+#In Alpha_Methods
+#Line # sets Color_Alpha, color opacity ##
+#Populate
+
+#Example
+    SkPaint paint;
+##
+
+##
+
 #Method void setARGB(U8CPU a, U8CPU r, U8CPU g, U8CPU b)
 #In Color_Methods
 #Line # sets color by component ##