docs: fix formatting of PULL_REQUEST_TEMPLATE.md (#26512)
docs: fix formatting of PULL_REQUEST_TEMPLATE.md (#26512)

This change enables developers to check the checkboxes or update them
after they submitted a PR.

PR Close #26512

gdi2290/angular,kegluneq/angular,alexeagle/angular,IgorMinar/angular,brandonroberts/angular,jasonaden/angular,wKoza/angular,juristr/angular,mgechev/angular,ultrasonicsoft/angular,jasonaden/angular,snaptech/angular,Toxicable/angular,ultrasonicsoft/angular,filipesilva/angular,ValtoFrameworks/Angular-2,Toxicable/angular,gdi2290/angular,petebacondarwin/angular,IdeaBlade/angular,hansl/angular,gkalpak/angular,mprobst/angular,Brocco/angular,alexeagle/angular,mhevery/angular,gkalpak/angular,matsko/angular,petebacondarwin/angular,gdi2290/angular,ocombe/angular,mhevery/angular,StephenFluin/angular,gdi2290/angular,blesh/angular,jasonaden/angular,hansl/angular,gdi2290/angular,mprobst/angular,vikerman/angular,manekinekko/angular,ValtoFrameworks/Angular-2,mlaval/angular,hansl/angular,juristr/angular,IdeaBlade/angular,filipesilva/angular,gkalpak/angular,brandonroberts/angular,mlaval/angular,StephenFluin/angular,gnomeontherun/angular,IgorMinar/angular,kegluneq/angular,IgorMinar/angular,Toxicable/angular,IgorMinar/angular,IgorMinar/angular,angular/angular,sarunint/angular,gnomeontherun/angular,petebacondarwin/angular,manekinekko/angular,Brocco/angular,brandonroberts/angular,angular/angular,juristr/angular,alxhub/angular,StephenFluin/angular,juristr/angular,matsko/angular,snaptech/angular,sarunint/angular,ultrasonicsoft/angular,wKoza/angular,wKoza/angular,mprobst/angular,filipesilva/angular,ultrasonicsoft/angular,alxhub/angular,vikerman/angular,Toxicable/angular,shairez/angular,shairez/angular,mprobst/angular,manekinekko/angular,mlaval/angular,filipesilva/angular,angular-indonesia/angular,IgorMinar/angular,brandonroberts/angular,brandonroberts/angular,JiaLiPassion/angular,gnomeontherun/angular,gnomeontherun/angular,ocombe/angular,JiaLiPassion/angular,matsko/angular,mprobst/angular,mlaval/angular,hansl/angular,kegluneq/angular,angular/angular,snaptech/angular,sarunint/angular,alxhub/angular,shairez/angular,IdeaBlade/angular,ValtoFrameworks/Angular-2,angular-indonesia/angular,mhevery/angular,jasonaden/angular,blesh/angular,petebacondarwin/angular,vikerman/angular,matsko/angular,ValtoFrameworks/Angular-2,jasonaden/angular,alxhub/angular,vikerman/angular,mhevery/angular,shairez/angular,ocombe/angular,brandonroberts/angular,Toxicable/angular,mhevery/angular,kegluneq/angular,angular/angular,manekinekko/angular,angular-indonesia/angular,mprobst/angular,vikerman/angular,vikerman/angular,Brocco/angular,gdi2290/angular,manekinekko/angular,sarunint/angular,manekinekko/angular,ultrasonicsoft/angular,kegluneq/angular,IdeaBlade/angular,Brocco/angular,JiaLiPassion/angular,angular-indonesia/angular,Brocco/angular,JiaLiPassion/angular,alexeagle/angular,blesh/angular,alexeagle/angular,hansl/angular,shairez/angular,IdeaBlade/angular,snaptech/angular,wKoza/angular,StephenFluin/angular,gkalpak/angular,ValtoFrameworks/Angular-2,ocombe/angular,filipesilva/angular,ultrasonicsoft/angular,wKoza/angular,mgechev/angular,kegluneq/angular,snaptech/angular,ocombe/angular,petebacondarwin/angular,snaptech/angular,mlaval/angular,alexeagle/angular,juristr/angular,mhevery/angular,mgechev/angular,wKoza/angular,jasonaden/angular,alxhub/angular,blesh/angular,mgechev/angular,hansl/angular,petebacondarwin/angular,mgechev/angular,blesh/angular,juristr/angular,StephenFluin/angular,Toxicable/angular,alexeagle/angular,sarunint/angular,ocombe/angular,Brocco/angular,sarunint/angular,matsko/angular