docs: Add import line to router event example for clarification (#42935)
docs: Add import line to router event example for clarification (#42935)

Without the `import {Event} from '@angular/router';`, the filter will
not work because the type is understood as the native `Event`.

Fixes #42920

PR Close #42935

angular-indonesia/angular,gkalpak/angular,ocombe/angular,brandonroberts/angular,gkalpak/angular,gnomeontherun/angular,ocombe/angular,JiaLiPassion/angular,gnomeontherun/angular,gkalpak/angular,manekinekko/angular,JiaLiPassion/angular,manekinekko/angular,gnomeontherun/angular,shairez/angular,shairez/angular,gnomeontherun/angular,angular/angular,brandonroberts/angular,ocombe/angular,manekinekko/angular,gkalpak/angular,angular-indonesia/angular,manekinekko/angular,JiaLiPassion/angular,brandonroberts/angular,ocombe/angular,manekinekko/angular,angular-indonesia/angular,brandonroberts/angular,shairez/angular,brandonroberts/angular,angular/angular,angular/angular,manekinekko/angular,angular-indonesia/angular,shairez/angular,ocombe/angular,angular/angular,brandonroberts/angular,JiaLiPassion/angular,ocombe/angular,shairez/angular