docs(changelog): cleanup 8.0.0 release notes (#30740)
docs(changelog): cleanup 8.0.0 release notes (#30740)

The removal of @angular/http is now mentioned under breaking changes.

This removes several duplicate entries from the changelog and removes
long and incorrect "closes" links to sources on Github. Those links were
present in the commit message and are incorrectly seen as issue references.

Additionally, code references are wrapped in backticks for proper formatting.

PR Close #30740

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