Random trivial fixes in the animation packages (#30276)

packages/flutter/lib/src/animation/animation_controller.dart

@@ -44,7 +44,7 @@ const Tolerance _kFlingTolerance = Tolerance(
 /// Configures how an [AnimationController] behaves when animations are disabled.
 ///
 /// When [AccessibilityFeatures.disableAnimations] is true, the device is asking
-/// flutter to reduce or disable animations as much as possible. To honor this,
+/// Flutter to reduce or disable animations as much as possible. To honor this,
 /// we reduce the duration and the corresponding number of frames for animations.
 /// This enum is used to allow certain [AnimationController]s to opt out of this
 /// behavior.
@@ -209,7 +209,7 @@ class AnimationController extends Animation<double>
   with AnimationEagerListenerMixin, AnimationLocalListenersMixin, AnimationLocalStatusListenersMixin {
   /// Creates an animation controller.
   ///
-  /// * [value] is the initial value of the animation. If defaults to the lower
+  /// * `value` is the initial value of the animation. If defaults to the lower
   ///   bound.
   ///
   /// * [duration] is the length of time this animation should last.
@@ -524,11 +524,10 @@ class AnimationController extends Animation<double>
     return _animateToInternal(target, duration: duration, curve: curve);
   }
 
-  TickerFuture _animateToInternal(double target, { Duration duration, Curve curve = Curves.linear, AnimationBehavior animationBehavior }) {
-    final AnimationBehavior behavior = animationBehavior ?? this.animationBehavior;
+  TickerFuture _animateToInternal(double target, { Duration duration, Curve curve = Curves.linear }) {
     double scale = 1.0;
     if (SemanticsBinding.instance.disableAnimations) {
-      switch (behavior) {
+      switch (animationBehavior) {
         case AnimationBehavior.normal:
           // Since the framework cannot handle zero duration animations, we run it at 5% of the normal
           // duration to limit most animations to a single frame.

packages/flutter/lib/src/animation/curves.dart

@@ -111,8 +111,8 @@ class SawTooth extends Curve {
   }
 }
 
-/// A curve that is 0.0 until [begin], then curved (according to [curve] from
-/// 0.0 to 1.0 at [end], then 1.0.
+/// A curve that is 0.0 until [begin], then curved (according to [curve]) from
+/// 0.0 at [begin] to 1.0 at [end], then remains 1.0 past [end].
 ///
 /// An [Interval] can be used to delay an animation. For example, a six second
 /// animation that uses an [Interval] with its [begin] set to 0.5 and its [end]

packages/flutter/lib/src/animation/tween_sequence.dart

@@ -7,17 +7,16 @@ import 'package:flutter/foundation.dart';
 import 'animation.dart';
 import 'tween.dart';
 
-/// Enables creating an [Animation] whose value is defined by a
-/// sequence of [Tween]s.
+/// Enables creating an [Animation] whose value is defined by a sequence of
+/// [Tween]s.
 ///
-/// Each [TweenSequenceItem] has a weight that defines its percentage
-/// of the animation's duration. Each tween defines the animation's value
-/// during the interval indicated by its weight.
+/// Each [TweenSequenceItem] has a weight that defines its percentage of the
+/// animation's duration. Each tween defines the animation's value during the
+/// interval indicated by its weight.
 ///
-/// For example, to define an animation that uses an easing curve to
-/// interpolate between 5.0 and 10.0 during the first 40% of the
-/// animation, remain at 10.0 for the next 20%, and then return to
-/// 10.0 for the final 40%:
+/// For example, to define an animation that uses an easing curve to interpolate
+/// between 5.0 and 10.0 during the first 40% of the animation, remain at 10.0
+/// for the next 20%, and then return to 10.0 for the final 40%:
 ///
 /// ```dart
 /// final Animation<double> animation = TweenSequence(
@@ -42,12 +41,11 @@ import 'tween.dart';
 class TweenSequence<T> extends Animatable<T> {
   /// Construct a TweenSequence.
   ///
-  /// The [items] parameter must be a list of one or more
-  /// [TweenSequenceItem]s.
+  /// The [items] parameter must be a list of one or more [TweenSequenceItem]s.
   ///
-  /// There's a small cost associated with building a `TweenSequence` so
-  /// it's best to reuse one, rather than rebuilding it on every frame,
-  /// when that's possible.
+  /// There's a small cost associated with building a `TweenSequence` so it's
+  /// best to reuse one, rather than rebuilding it on every frame, when that's
+  /// possible.
   TweenSequence(List<TweenSequenceItem<T>> items)
       : assert(items != null),
         assert(items.isNotEmpty) {
@@ -124,8 +122,8 @@ class TweenSequenceItem<T> {
   /// An arbitrary value that indicates the relative percentage of a
   /// [TweenSequence] animation's duration when [tween] will be used.
   ///
-  /// The percentage for an individual item is the item's weight divided
-  /// by the sum of all of the items' weights.
+  /// The percentage for an individual item is the item's weight divided by the
+  /// sum of all of the items' weights.
   final double weight;
 }