docs: remove mat stylers from docs (#3517)

* docs: remove mat stylers from docs

* add one more

src/lib/grid-list/grid-tile.ts

@@ -69,6 +69,7 @@ export class MdGridTileText implements AfterContentInit {
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: '[md-grid-avatar], [mat-grid-avatar]',
@@ -80,6 +81,7 @@ export class MdGridAvatarCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-grid-tile-header, mat-grid-tile-header',
@@ -91,6 +93,7 @@ export class MdGridTileHeaderCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-grid-tile-footer, mat-grid-tile-footer',

src/lib/list/list.ts

@@ -29,6 +29,7 @@ export class MdList {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-list, mat-list',
@@ -40,6 +41,7 @@ export class MdListCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-nav-list, mat-nav-list',
@@ -51,6 +53,7 @@ export class MdNavListCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-divider, mat-divider',
@@ -60,7 +63,10 @@ export class MdNavListCssMatStyler {}
 })
 export class MdDividerCssMatStyler {}
 
-/* Need directive for a ContentChild query in list-item */
+/**
+ * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
+ */
 @Directive({
   selector: '[md-list-avatar], [mat-list-avatar]',
   host: {
@@ -69,7 +75,10 @@ export class MdDividerCssMatStyler {}
 })
 export class MdListAvatarCssMatStyler {}
 
-/* Need directive to add mat- CSS styling */
+/**
+ * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
+ */
 @Directive({
   selector: '[md-list-icon], [mat-list-icon]',
   host: {
@@ -80,6 +89,7 @@ export class MdListIconCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: '[md-subheader], [mat-subheader]',

src/lib/progress-spinner/progress-spinner.ts

@@ -33,6 +33,7 @@ type EasingFn = (currentTime: number, startValue: number,
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-progress-spinner, mat-progress-spinner',
@@ -45,6 +46,7 @@ export class MdProgressSpinnerCssMatStyler {}
 
 /**
  * Directive whose purpose is to add the mat- CSS styling to this selector.
+ * @docs-private
  */
 @Directive({
   selector: 'md-progress-circle, mat-progress-circle',