docs(aio): move links from nav groups to items
docs(aio): move links from nav groups to items

Fundamentals and Techniques nav groups we also links to pages. This caused
counterintuitive behaviour when clicking on them.

This commit moves each link from the group item to a children item, called
Introduction.

Closes #16604

robwormald/angular,shairez/angular,Brocco/angular,jonrimmer/angular,hansl/angular,Brocco/angular,gkalpak/angular,ocombe/angular,mdegoo/angular,JiaLiPassion/angular,ghetolay/angular,dsebastien/angular,trshafer/angular,vamsivarikuti/angular,shairez/angular,vamsivarikuti/angular,jonrimmer/angular,kegluneq/angular,jasonaden/angular,mlaval/angular,Brocco/angular,ghetolay/angular,LucasSloan/angular,aboveyou00/angular,chuckjaz/angular,mdegoo/angular,cexbrayat/angular,dtoroshin/n2oDoc,pkozlowski-opensource/angular,gnomeontherun/angular,dsebastien/angular,vikerman/angular,manekinekko/angular,aboveyou00/angular,angular/angular,trshafer/angular,Toxicable/angular,wKoza/angular,heathkit/angular,blesh/angular,JiaLiPassion/angular,dsebastien/angular,juleskremer/angular,ocombe/angular,gnomeontherun/angular,petebacondarwin/angular,mhevery/angular,mzgol/angular,kara/angular,Toxicable/angular,ultrasonicsoft/angular,petebacondarwin/angular,ocombe/angular,mlaval/angular,dtoroshin/n2oDoc,meeroslav/angular,gjungb/angular,mlaval/angular,angularbrasil/angular,shairez/angular,jonrimmer/angular,ghetolay/angular,alexeagle/angular,nosovk/angular,sarunint/angular,dtoroshin/n2oDoc,tbosch/angular,mgiambalvo/angular,vamsivarikuti/angular,sarunint/angular,alexeagle/angular,alexeagle/angular,angularbrasil/angular,aboveyou00/angular,meeroslav/angular,hansl/angular,kegluneq/angular,meeroslav/angular,alexeagle/angular,chuckjaz/angular,ultrasonicsoft/angular,pk-karthik/framework-js-angular,nosovk/angular,filipesilva/angular,souvikbasu/angular,ghetolay/angular,kwalrath/angular,manekinekko/angular,mgiambalvo/angular,wKoza/angular,brandonroberts/angular,shairez/angular,heathkit/angular,mgiambalvo/angular,mzgol/angular,manekinekko/angular,angularbrasil/angular,brandonroberts/angular,robwormald/angular,smartm0use/angular,ValtoFrameworks/Angular-2,angular/angular,souvikbasu/angular,gkalpak/angular,nosovk/angular,StephenFluin/angular,meeroslav/angular,angular/angular,mlaval/angular,aboveyou00/angular,NathanWalker/angular,ValtoFrameworks/Angular-2,angularbrasil/angular,rkirov/angular,gnomeontherun/angular,juleskremer/angular,dsebastien/angular,vikerman/angular,dtoroshin/n2oDoc,filipesilva/angular,wKoza/angular,juristr/angular,wKoza/angular,LucasSloan/angular,aboveyou00/angular,cironunes/angular,chuckjaz/angular,mgol/angular,IgorMinar/angular,juristr/angular,kegluneq/angular,pkozlowski-opensource/angular,tbosch/angular,vicb/angular,IgorMinar/angular,kwalrath/angular,hansl/angular,chalin/angular,shairez/angular,rkirov/angular,IdeaBlade/angular,cironunes/angular,nosovk/angular,gdi2290/angular,matsko/angular,IgorMinar/angular,vicb/angular,mgol/angular,souvikbasu/angular,trshafer/angular,juleskremer/angular,souvikbasu/angular,snaptech/angular,filipesilva/angular,angular-indonesia/angular,brandonroberts/angular,vikerman/angular,matsko/angular,vsavkin/angular,cexbrayat/angular,StephenFluin/angular,matsko/angular,ValtoFrameworks/Angular-2,alxhub/angular,JiaLiPassion/angular,pk-karthik/framework-js-angular,kara/angular,matsko/angular,petebacondarwin/angular,mgechev/angular,gdi2290/angular,IdeaBlade/angular,Toxicable/angular,pkozlowski-opensource/angular,kara/angular,juristr/angular,jasonaden/angular,mdegoo/angular,cexbrayat/angular,mlaval/angular,kara/angular,Brocco/angular,juleskremer/angular,juleskremer/angular,mprobst/angular,robwormald/angular,brandonroberts/angular,NathanWalker/angular,heathkit/angular,vsavkin/angular,gdi2290/angular,StephenFluin/angular,robwormald/angular,filipesilva/angular,robwormald/angular,sarunint/angular,snaptech/angular,jasonaden/angular,mgechev/angular,LucasSloan/angular,wKoza/angular,NathanWalker/angular,IdeaBlade/angular,pkozlowski-opensource/angular,gkalpak/angular,angular-indonesia/angular,alexeagle/angular,smartm0use/angular,mgechev/angular,IdeaBlade/angular,petebacondarwin/angular,kwalrath/angular,ValtoFrameworks/Angular-2,jasonaden/angular,vicb/angular,LucasSloan/angular,chuckjaz/angular,gjungb/angular,meeroslav/angular,jasonaden/angular,aboveyou00/angular,NathanWalker/angular,juristr/angular,IgorMinar/angular,ghetolay/angular,ValtoFrameworks/Angular-2,kara/angular,alexeagle/angular,angular-indonesia/angular,rjamet/angular,robwormald/angular,manekinekko/angular,mhevery/angular,brandonroberts/angular,mhevery/angular,vsavkin/angular,gjungb/angular,cironunes/angular,smartm0use/angular,mhevery/angular,mhevery/angular,snaptech/angular,alxhub/angular,alxhub/angular,souvikbasu/angular,mgiambalvo/angular,Brocco/angular,kegluneq/angular,StephenFluin/angular,snaptech/angular,IdeaBlade/angular,juristr/angular,mprobst/angular,smartm0use/angular,ultrasonicsoft/angular,cexbrayat/angular,ocombe/angular,alxhub/angular,rjamet/angular,chalin/angular,JiaLiPassion/angular,chalin/angular,sarunint/angular,mdegoo/angular,snaptech/angular,ultrasonicsoft/angular,cexbrayat/angular,matsko/angular,kegluneq/angular,StephenFluin/angular,Toxicable/angular,mgiambalvo/angular,vsavkin/angular,vsavkin/angular,vamsivarikuti/angular,pk-karthik/framework-js-angular,hansl/angular,juristr/angular,kara/angular,jonrimmer/angular,chuckjaz/angular,rkirov/angular,angular-indonesia/angular,manekinekko/angular,sarunint/angular,jonrimmer/angular,vikerman/angular,tbosch/angular,NathanWalker/angular,tbosch/angular,ultrasonicsoft/angular,mdegoo/angular,snaptech/angular,pk-karthik/framework-js-angular,rkirov/angular,trshafer/angular,LucasSloan/angular,gkalpak/angular,mhevery/angular,trshafer/angular,blesh/angular,heathkit/angular,gdi2290/angular,mzgol/angular,alxhub/angular,vikerman/angular,sarunint/angular,vicb/angular,angularbrasil/angular,kwalrath/angular,trshafer/angular,mgol/angular,LucasSloan/angular,vikerman/angular,blesh/angular,vicb/angular,mzgol/angular,hansl/angular,rkirov/angular,IgorMinar/angular,mprobst/angular,petebacondarwin/angular,Toxicable/angular,cironunes/angular,ocombe/angular,cironunes/angular,tbosch/angular,gdi2290/angular,IgorMinar/angular,mgol/angular,petebacondarwin/angular,cironunes/angular,dsebastien/angular,kegluneq/angular,rjamet/angular,hansl/angular,mgol/angular,chalin/angular,Toxicable/angular,dsebastien/angular,mgechev/angular,gjungb/angular,gjungb/angular,filipesilva/angular,mprobst/angular,mzgol/angular,rkirov/angular,blesh/angular,chuckjaz/angular,mgol/angular,ocombe/angular,jasonaden/angular,mzgol/angular,dtoroshin/n2oDoc,angularbrasil/angular,kwalrath/angular,smartm0use/angular,mgechev/angular,pkozlowski-opensource/angular,wKoza/angular,pk-karthik/framework-js-angular,angular/angular,vicb/angular,heathkit/angular,rjamet/angular,mdegoo/angular,gdi2290/angular,brandonroberts/angular,mprobst/angular,blesh/angular,ultrasonicsoft/angular,NathanWalker/angular,mprobst/angular,vamsivarikuti/angular,heathkit/angular,nosovk/angular,jonrimmer/angular,Brocco/angular,manekinekko/angular,gnomeontherun/angular