Check every word in docs

This enables checking all text to see if it
either represents a valid reference or is a
word in docs/spelling.txt . Expressions are
checked for validity as well.

There are a few shortcuts (marked with TODO):
- typedefs aren't resolved, so cheats are
added for SkVector and SkIVector.
- operator overload detection is incomplete
- constructor detection is incomplete
- formula definitions aren't detected

Found and fixed a bunch of spelling, usage,
and incorrect or obsolete references.

A few comment changes are needed in
include/core to get this to work, mostly
centered around recent SkPaint/SkFont edits.

TBR=reed@google.com
Docs-Preview: https://skia.org/?cl=167541
Bug: skia:
Change-Id: I2e0d5990105c5a8482b0c0d3e50fd0b330996dd6
Reviewed-on: https://skia-review.googlesource.com/c/167541
Reviewed-by: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
Commit-Queue: Cary Clark <caryclark@skia.org>
diff --git a/docs/SkMatrix_Reference.bmh b/docs/SkMatrix_Reference.bmh
index 17ceab5..0b98658 100644
--- a/docs/SkMatrix_Reference.bmh
+++ b/docs/SkMatrix_Reference.bmh
@@ -8,7 +8,7 @@
 #Populate
 ##
 
-Matrix holds a 3x3 matrix for transforming coordinates. This allows mapping
+Matrix holds a 3 by 3 matrix for transforming coordinates. This allows mapping
 Points and Vectors with translation, scaling, skewing, rotation, and
 perspective.
 
@@ -24,7 +24,7 @@
 
 #Method static SkMatrix MakeScale(SkScalar sx, SkScalar sy)
 #In Constructors
-#Line # constructs from scale in x and y ##
+#Line # constructs from scale on x-axis and y-axis ##
 #Populate
 
 #Example
@@ -56,7 +56,7 @@
 
 #Method static SkMatrix MakeTrans(SkScalar dx, SkScalar dy)
 #In Constructors
-#Line # constructs from translate in x and y ##
+#Line # constructs from translate on x-axis and y-axis ##
 #Populate
 
 #Example
@@ -108,7 +108,7 @@
 #Populate
 ##
 
-Enum of bit fields for mask returned by getType.
+Enumeration of bit fields for mask returned by getType.
 Used to identify the complexity of Matrix, to optimize performance.
 
 #Const kIdentity_Mask 0
@@ -121,7 +121,7 @@
 ##
 #Const kScale_Mask 2
 #Line # scale Matrix ##
-set if Matrix has x or y scale
+set if Matrix scales x-axis or y-axis
 ##
 #Const kAffine_Mask 4
 #Line # skew or rotate Matrix ##
@@ -1129,7 +1129,7 @@
 #Method void setTranslate(SkScalar dx, SkScalar dy)
 #In Constructors
 #In Set
-#Line # sets to translate in x and y ##
+#Line # sets to translate on x-axis and y-axis ##
 #Populate
 
 #Example
@@ -1722,8 +1722,8 @@
 #In Set
 #In Operators
 #Line # post-multiplies Matrix by inverse scale ##
-Sets Matrix to Matrix constructed from scaling by #Formula # (1/divx, 1/divy) ##,
-about pivot point (px, py), multiplied by Matrix.
+Sets Matrix to Matrix constructed from scaling by (1/divx, 1/divy),
+multiplied by Matrix.
 
 Returns false if either divx or divy is zero.
 
@@ -1753,8 +1753,8 @@
                          |  0  0  1 | | P Q R |   |    P    Q    R |
 ##
 
-#Param divx  integer divisor for inverse scale in x ##
-#Param divy  integer divisor for inverse scale in y ##
+#Param divx  integer divisor for inverse scale on x-axis ##
+#Param divy  integer divisor for inverse scale on y-axis ##
 
 #Return  true on successful scale ##
 
@@ -1902,10 +1902,10 @@
 how Matrix maps to the side or center of the destination Rect.
 
 #Const kFill_ScaleToFit 0
-#Line # scales in x and y to fill destination Rect ##
-    Computes Matrix that scales in x and y independently, so that source Rect is
-    mapped to completely fill destination Rect. The aspect ratio of source Rect
-    may change.
+#Line # scales about x-axis and y-axis to fill destination Rect ##
+    Computes Matrix that scales about x-axis and y-axis independently, so that
+    source Rect is mapped to completely fill destination Rect. The aspect ratio
+    of source Rect may change.
 ##
 #Const kStart_ScaleToFit 1
 #Line # scales and aligns to left and top ##
@@ -2603,7 +2603,7 @@
 # ------------------------------------------------------------------------------
 #Method bool isFixedStepInX() const
 #In Property
-#Line # returns if transformation supports fixed step in x ##
+#Line # returns if transformation supports fixed step on x-axis ##
 #Populate
 
 #Example
@@ -2645,7 +2645,7 @@
 
 #Method SkVector fixedStepInX(SkScalar y) const
 #In Property
-#Line # returns step in x for a position in y ##
+#Line # returns step on x-axis for a position on y-axis ##
 #Populate
 
 #Example
@@ -2941,7 +2941,7 @@
 ##
 ##
 
-#SeeAlso SeeAlso getType
+#SeeAlso getType
 
 ##