docs: fix minor grammar mistakes in What is Angular topic (#40892)
docs: fix minor grammar mistakes in What is Angular topic (#40892)

PR Close #40892

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