Improve documentation strings

@@ -5,6 +5,7 @@
 - Apply BoxShape and BorderRadius to selected Checkbox [Joseph Grabinger]
 - Fix Color.toHex()
 - Improve Annotations placement
+- Improve documentation strings
 
 ## 3.9.0
 

@@ -25,58 +25,58 @@ import 'obj/object_dict.dart';
 import 'obj/smask.dart';
 
 enum PdfBlendMode {
-  /// Selects the source colour, ignoring the backdrop
+  /// Selects the source color, ignoring the backdrop
   normal,
 
-  /// Multiplies the backdrop and source colour values
+  /// Multiplies the backdrop and source color values
   multiply,
 
-  /// Multiplies the complements of the backdrop and source colour values,
+  /// Multiplies the complements of the backdrop and source color values,
   /// then complements the result
   screen,
 
-  /// Multiplies or screens the colours, depending on the backdrop colour value
+  /// Multiplies or screens the colors, depending on the backdrop color value
   overlay,
 
-  /// Selects the darker of the backdrop and source colours
+  /// Selects the darker of the backdrop and source colors
   darken,
 
-  /// Selects the lighter of the backdrop and source colours
+  /// Selects the lighter of the backdrop and source colors
   lighten,
 
-  /// Brightens the backdrop colour to reflect the source colour.
+  /// Brightens the backdrop color to reflect the source color.
   /// Painting with black produces no changes.
   colorDodge,
 
-  /// Darkens the backdrop colour to reflect the source colour
+  /// Darkens the backdrop color to reflect the source color
   colorBurn,
 
-  /// Multiplies or screens the colours, depending on the source colour value
+  /// Multiplies or screens the colors, depending on the source color value
   hardLight,
 
-  /// Darkens or lightens the colours, depending on the source colour value
+  /// Darkens or lightens the colors, depending on the source color value
   softLight,
 
-  /// Subtracts the darker of the two constituent colours from the lighter colour
+  /// Subtracts the darker of the two constituent colors from the lighter color
   difference,
 
   /// Produces an effect similar to that of the Difference mode but lower in contrast
   exclusion,
 
-  /// Creates a colour with the hue of the source colour and the saturation and
-  /// luminosity of the backdrop colour
+  /// Creates a color with the hue of the source color and the saturation and
+  /// luminosity of the backdrop color
   hue,
 
-  /// Creates a colour with the saturation of the source colour and the hue and
-  /// luminosity of the backdrop colour
+  /// Creates a color with the saturation of the source color and the hue and
+  /// luminosity of the backdrop color
   saturation,
 
-  /// Creates a colour with the hue and saturation of the source colour and the
-  /// luminosity of the backdrop colour
+  /// Creates a color with the hue and saturation of the source color and the
+  /// luminosity of the backdrop color
   color,
 
-  /// Creates a colour with the luminosity of the source colour and the hue and
-  /// saturation of the backdrop colour
+  /// Creates a color with the luminosity of the source color and the hue and
+  /// saturation of the backdrop color
   luminosity,
 }
 

@@ -35,17 +35,17 @@ import 'stream.dart';
 
 /// Shape to be used at the corners of paths that are stroked
 enum PdfLineJoin {
-  /// The outer edges of the strokes for the two segments shall beextended until they meet at an angle, as in a picture frame. If the segments meet at too sharp an angle (as defined by the miter limit parameter, a bevel join shall be used instead.
+  /// The outer edges of the strokes for the two segments shall be extended until they meet at an angle, as in a picture frame. If the segments meet at too sharp an angle (as defined by the miter limit parameter, a bevel join shall be used instead.
   miter,
 
-  /// An arc of a circle with a diameter equal to the line width shall be drawn around the point where the two segments meet, connecting the outer edges of the strokes for the two segments. This pieslice-shaped figure shall be filled in, producing a rounded corner.
+  /// An arc of a circle with a diameter equal to the line width shall be drawn around the point where the two segments meet, connecting the outer edges of the strokes for the two segments. This pie-slice-shaped figure shall be filled in, producing a rounded corner.
   round,
 
   /// The two segments shall be finished with butt caps and the resulting notch beyond the ends of the segments shall be filled with a triangle.
   bevel
 }
 
-/// Specify the shape that shall be used at the ends of open subpaths
+/// Specify the shape that shall be used at the ends of open sub paths
 /// and dashes, when they are stroked.
 enum PdfLineCap {
   /// The stroke shall be squared off at the endpoint of the path. There shall be no projection beyond the end of the path.
@@ -54,7 +54,7 @@ enum PdfLineCap {
   /// A semicircular arc with a diameter equal to the line width shall be drawn around the endpoint and shall be filled in.
   round,
 
-  /// The stroke shall continue beyond the endpoint of the path for a distance equal to half the line width and shall besquared off.
+  /// The stroke shall continue beyond the endpoint of the path for a distance equal to half the line width and shall be squared off.
   square
 }
 
@@ -216,7 +216,7 @@ class PdfGraphics {
     }
   }
 
-  /// Save the graphc context
+  /// Save the graphic context
   void saveContext() {
     assert(() {
       if (_page.pdfDocument.verbose) {
@@ -291,7 +291,7 @@ class PdfGraphics {
 
   /// Draws an ellipse
   ///
-  /// Use clockwise=false to draw the inside of a donnnut
+  /// Use clockwise=false to draw the inside of a donut
   void drawEllipse(double x, double y, double r1, double r2,
       {bool clockwise = true}) {
     assert(() {

@@ -51,7 +51,7 @@ class PdfCatalog extends PdfObjectDict {
   /// The page labels of the document
   PdfPageLabels? pageLabels;
 
-  /// These map the page modes just defined to the pagemodes setting of Pdf.
+  /// These map the page modes just defined to the page modes setting of the Pdf.
   static const List<String> _pdfPageModes = <String>[
     '/UseNone',
     '/UseOutlines',

@@ -95,7 +95,7 @@ class PdfXrefTable extends PdfDataType {
   /// Contains offsets of each object
   final offsets = <PdfXref>[];
 
-  /// Add a xross reference element to the set
+  /// Add a cross reference element to the set
   void add(PdfXref xref) {
     offsets.add(xref);
   }