docs: fix header mistake (#31811)
docs: fix header mistake (#31811)

The code example refers to `src/app/heroes/heroes.component.html` but its header was `src/app/hero.service.ts` which was obviously a mistake.
PR Close #31811

alexeagle/angular,gkalpak/angular,JiaLiPassion/angular,filipesilva/angular,gdi2290/angular,angular-indonesia/angular,mgechev/angular,sarunint/angular,gkalpak/angular,shairez/angular,snaptech/angular,ocombe/angular,alxhub/angular,mprobst/angular,gdi2290/angular,gdi2290/angular,brandonroberts/angular,Brocco/angular,ocombe/angular,blesh/angular,snaptech/angular,matsko/angular,gnomeontherun/angular,brandonroberts/angular,sarunint/angular,mprobst/angular,Toxicable/angular,shairez/angular,snaptech/angular,StephenFluin/angular,manekinekko/angular,angular-indonesia/angular,JiaLiPassion/angular,sarunint/angular,blesh/angular,ocombe/angular,gnomeontherun/angular,StephenFluin/angular,wKoza/angular,Toxicable/angular,wKoza/angular,IdeaBlade/angular,JiaLiPassion/angular,wKoza/angular,manekinekko/angular,Toxicable/angular,alexeagle/angular,gdi2290/angular,wKoza/angular,angular/angular,alxhub/angular,gdi2290/angular,shairez/angular,sarunint/angular,mgechev/angular,Brocco/angular,manekinekko/angular,gdi2290/angular,gnomeontherun/angular,mgechev/angular,manekinekko/angular,manekinekko/angular,mprobst/angular,shairez/angular,brandonroberts/angular,Brocco/angular,Brocco/angular,mhevery/angular,mprobst/angular,angular-indonesia/angular,alexeagle/angular,IdeaBlade/angular,matsko/angular,ocombe/angular,mgechev/angular,alexeagle/angular,StephenFluin/angular,matsko/angular,StephenFluin/angular,mhevery/angular,Brocco/angular,alexeagle/angular,matsko/angular,mhevery/angular,angular-indonesia/angular,filipesilva/angular,Toxicable/angular,brandonroberts/angular,blesh/angular,alxhub/angular,alexeagle/angular,vikerman/angular,gkalpak/angular,filipesilva/angular,gkalpak/angular,StephenFluin/angular,wKoza/angular,manekinekko/angular,mgechev/angular,ocombe/angular,IdeaBlade/angular,shairez/angular,Toxicable/angular,snaptech/angular,vikerman/angular,filipesilva/angular,snaptech/angular,gnomeontherun/angular,mhevery/angular,vikerman/angular,matsko/angular,sarunint/angular,IdeaBlade/angular,angular/angular,blesh/angular,angular/angular,wKoza/angular,alxhub/angular,mprobst/angular,vikerman/angular,vikerman/angular,vikerman/angular,sarunint/angular,mhevery/angular,brandonroberts/angular,snaptech/angular,IdeaBlade/angular,angular/angular,mhevery/angular,JiaLiPassion/angular,blesh/angular,filipesilva/angular,Toxicable/angular,ocombe/angular,alxhub/angular,mprobst/angular,Brocco/angular,brandonroberts/angular