docs: add api stability indicators for @angular/common

modules/@angular/common/src/pipes/async_pipe.ts

@@ -59,6 +59,8 @@ var __unused: Promise<any>;  // avoid unused import when Promise union types are
  * to the view. Every 500ms, the `time` Observable updates the view with the current time.
  *
  * {@example core/pipes/ts/async_pipe/async_pipe_example.ts region='AsyncPipeObservable'}
+ *
+ * @stable
  */
 @Pipe({name: 'async', pure: false})
 @Injectable()

modules/@angular/common/src/pipes/common_pipes.ts

@@ -20,6 +20,8 @@ import {I18nSelectPipe} from './i18n_select_pipe';
  *
  * This collection can be used to quickly enumerate all the built-in pipes in the `pipes`
  * property of the `@Component` decorator.
+ *
+ * @experimental Contains i18n pipes which are experimental
  */
 export const COMMON_PIPES = /*@ts2dart_const*/[
   AsyncPipe,

modules/@angular/common/src/pipes/date_pipe.ts

@@ -81,6 +81,8 @@ var defaultLocale: string = 'en-US';
  * ```
  *
  * {@example core/pipes/ts/date_pipe/date_pipe_example.ts region='DatePipe'}
+ *
+ * @experimental
  */
 @Pipe({name: 'date', pure: true})
 @Injectable()

modules/@angular/common/src/pipes/i18n_plural_pipe.ts

@@ -34,9 +34,9 @@ var interpolationExp: RegExp = RegExpWrapper.create('#');
  *  }
  *  ```
  *
+ * @experimental
  */
 @Pipe({name: 'i18nPlural', pure: true})
-@Injectable()
 export class I18nPluralPipe implements PipeTransform {
   transform(value: number, pluralMap: {[count: string]: string}): string {
     var key: string;

modules/@angular/common/src/pipes/i18n_select_pipe.ts

@@ -31,9 +31,10 @@ import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
  *    ...
  *  }
  *  ```
+ *
+ *  @experimental
  */
 @Pipe({name: 'i18nSelect', pure: true})
-@Injectable()
 export class I18nSelectPipe implements PipeTransform {
   transform(value: string, mapping: {[key: string]: string}): string {
     if (!isStringMap(mapping)) {

modules/@angular/common/src/pipes/json_pipe.ts

@@ -7,10 +7,10 @@ import {Json} from '../../src/facade/lang';
  *
  * ### Example
  * {@example core/pipes/ts/json_pipe/json_pipe_example.ts region='JsonPipe'}
+ *
+ * @stable
  */
-/* @ts2dart_const */
 @Pipe({name: 'json', pure: false})
-@Injectable()
 export class JsonPipe implements PipeTransform {
   transform(value: any): string { return Json.stringify(value); }
 }

modules/@angular/common/src/pipes/lowercase_pipe.ts

@@ -8,10 +8,10 @@ import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
  * ### Example
  *
  * {@example core/pipes/ts/lowerupper_pipe/lowerupper_pipe_example.ts region='LowerUpperPipe'}
+ *
+ * @experimental
  */
-/* @ts2dart_const */
 @Pipe({name: 'lowercase'})
-@Injectable()
 export class LowerCasePipe implements PipeTransform {
   transform(value: string): string {
     if (isBlank(value)) return value;

modules/@angular/common/src/pipes/replace_pipe.ts

@@ -35,6 +35,10 @@ import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
  * --Note--: The 'pattern' parameter will be converted to a RegExp instance. Make sure to escape the
  * string properly if you are matching for regular expression special characters like parenthesis,
  * brackets etc.
+ *
+ * @deprecated The current pipe has limited functionality. The pipe api is not meant to be able
+ * express complex yet generic value transformations. We recommend that these transformations happen
+ * in the component logic instead.
  */
 
 @Pipe({name: 'replace'})

modules/@angular/common/src/pipes/slice_pipe.ts

@@ -58,10 +58,11 @@ import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
  * ## String Examples
  *
  * {@example core/pipes/ts/slice_pipe/slice_pipe_example.ts region='SlicePipe_string'}
+ *
+ * @stable
  */
 
 @Pipe({name: 'slice', pure: false})
-@Injectable()
 export class SlicePipe implements PipeTransform {
   transform(value: any, start: number, end: number = null): any {
     if (isBlank(value)) return value;

modules/@angular/common/src/pipes/uppercase_pipe.ts

@@ -8,9 +8,10 @@ import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
  * ### Example
  *
  * {@example core/pipes/ts/lowerupper_pipe/lowerupper_pipe_example.ts region='LowerUpperPipe'}
+ *
+ * @experimental
  */
 @Pipe({name: 'uppercase'})
-@Injectable()
 export class UpperCasePipe implements PipeTransform {
   transform(value: string): string {
     if (isBlank(value)) return value;