docs(autocomplete): fix a11y of autocomplete example

Author: kara

src/demo-app/autocomplete/autocomplete-demo.ts

@@ -88,7 +88,8 @@ export class AutocompleteDemo {
   }
 
   filterStates(val: string) {
-    return val ? this.states.filter((s) => s.name.match(new RegExp(val, 'gi'))) : this.states;
+    return val ? this.states.filter(s => new RegExp(`^${val}`, 'gi').test(s.name))
+               : this.states;
   }
 
 }

src/examples/autocomplete-overview/autocomplete-overview-example.ts

@@ -71,7 +71,8 @@ export class AutocompleteOverviewExample {
   }
 
   filterStates(val: string) {
-    return val ? this.states.filter((s) => new RegExp(val, 'gi').test(s)) : this.states;
+    return val ? this.states.filter(s => new RegExp(`^${val}`, 'gi').test(s))
+               : this.states;
   }
 
 }

src/lib/autocomplete/autocomplete.md

@@ -75,7 +75,7 @@ class MyComp {
    }
 
    filter(val: string): string[] {
-      return this.options.filter(option => new RegExp(val, 'gi').test(option)); 
+      return this.options.filter(option => new RegExp(`^${val}`, 'gi').test(option)); 
    }
 }
 ```
@@ -134,7 +134,7 @@ class MyComp {
    }
 
    filter(name: string): User[] {
-      return this.options.filter(option => new RegExp(name, 'gi').test(option)); 
+      return this.options.filter(option => new RegExp(`^${name}`, 'gi').test(option)); 
    }
 
    displayFn(user: User): string {