strings: Add examples for HasPrefix and HasSuffix
strings: Add examples for HasPrefix and HasSuffix

These methods didn't had any examples, so added them. Examples makes things more clear
diff --git a/src/strings/example_test.go b/src/strings/example_test.go
index 7243e16..b7763bb 100644
--- a/src/strings/example_test.go
+++ b/src/strings/example_test.go
@@ -223,3 +223,19 @@ func ExampleTrimPrefix() {
 	fmt.Print("Hello" + s)
 	// Output: Hello, world!
 }
+
+func ExampleHasPrefix() {
+	fmt.Println(strings.HasPrefix("hello", "hell"))
+	fmt.Println(strings.HasPrefix("hello", "heaven"))
+	// Output:
+	// true
+	// false
+}
+
+func ExampleHasSuffix() {
+	fmt.Println(strings.HasSuffix("hello", "llo"))
+	fmt.Println(strings.HasSuffix("hello", "hell"))
+	// Output:
+	// true
+	// false
+}

Change-Id: I5d451c669bd05e19a2afc33ed2ec59b280c2c2d9
Reviewed-on: https://go-review.googlesource.com/12065
Reviewed-by: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

Endika/go,josharian/go,ImJasonH/go,polyverse-security/go,theif519/go,kim-racktop/go,fjballest/golang,josharian/go,goodlang/good,theif519/go,akutz/go,vanloswang/go,josharian/go,fjballest/golang,golang/go,binarycrusader/go,ImJasonH/go,rachtsingh/gogojuice,gdey/go,nawawi/go,roth1002/go,fjballest/golang,ganboing/go-esx,Cofyc/go,cloudflare/go,Jordanzuo/go,linux-on-ibm-z/go,CAFxX/go,akutz/go,CAFxX/go,theif519/go,miolini/go,fjballest/golang,linux-on-ibm-z/go,golang/go,theif519/go,Cofyc/go,vsekhar/elastic-go,momchil-velikov/go,codestation/go,4ad/go,josharian/go,vanloswang/go,cyberroadie/go,kim-racktop/go,ganboing/go-esx,CAFxX/go,gdey/go,4ad/go,mwhudson/go,cloudflare/go,derekmarcotte/go,Endika/go,Endika/go,malvira/go,sndnvaps/go,deft-code/go,rachtsingh/gogojuice,cyberroadie/go,deft-code/go,kim-racktop/go,malvira/go,CAFxX/go,Jordanzuo/go,ganboing/go-esx,linux-on-ibm-z/go,miolini/go,deft-code/go,miolini/go,rachtsingh/gogojuice,mwhudson/go,odeke-em/go,goodlang/good,fjballest/golang,mwhudson/go,kim-racktop/go,malvira/go,gdey/go,vanloswang/go,ImJasonH/go,miolini/go,fjballest/golang,ImJasonH/go,4ad/go,Jordanzuo/go,vsekhar/elastic-go,miolini/go,Samurais/go,akutz/go,golang/go,derekmarcotte/go,Endika/go,linux-on-ibm-z/go,odeke-em/go,deft-code/go,linux-on-ibm-z/go,CAFxX/go,akutz/go,sndnvaps/go,theif519/go,polyverse-security/go,Samurais/go,vsekhar/elastic-go,kim-racktop/go,cloudflare/go,derekmarcotte/go,cyberroadie/go,vanloswang/go,odeke-em/go,derekmarcotte/go,vanloswang/go,theif519/go,4ad/go,suncycheng/go,Cofyc/go,suncycheng/go,malvira/go,ImJasonH/go,polyverse-security/go,Samurais/go,momchil-velikov/go,sndnvaps/go,Endika/go,josharian/go,binarycrusader/go,cyberroadie/go,rachtsingh/gogojuice,cyberroadie/go,deft-code/go,sndnvaps/go,derekmarcotte/go,Endika/go,akutz/go,momchil-velikov/go,goodlang/good,sndnvaps/go,suncycheng/go,binarycrusader/go,cyberroadie/go,kim-racktop/go,CAFxX/go,Endika/go,gdey/go,miolini/go,Samurais/go,Samurais/go,odeke-em/go,rachtsingh/gogojuice,kim-racktop/go,golang/go,ImJasonH/go,odeke-em/go,derekmarcotte/go,cloudflare/go,malvira/go,momchil-velikov/go,vsekhar/elastic-go,Jordanzuo/go,theif519/go,momchil-velikov/go,Cofyc/go,Cofyc/go,suncycheng/go,Cofyc/go,codestation/go,rachtsingh/gogojuice,malvira/go,suncycheng/go,golang/go,golang/go,binarycrusader/go,polyverse-security/go,codestation/go,momchil-velikov/go,odeke-em/go,ImJasonH/go,malvira/go,codestation/go,akutz/go,deft-code/go,deft-code/go,Jordanzuo/go,ImJasonH/go,christopher-henderson/Go,nawawi/go,cyberroadie/go,suncycheng/go,derekmarcotte/go,cloudflare/go,josharian/go,Endika/go,4ad/go,codestation/go,nawawi/go,goodlang/good,codestation/go,momchil-velikov/go,malvira/go,codestation/go,mwhudson/go,vsekhar/elastic-go,CAFxX/go,sndnvaps/go,nawawi/go,Jordanzuo/go,vanloswang/go,linux-on-ibm-z/go,akutz/go,odeke-em/go,fjballest/golang,cloudflare/go,kim-racktop/go,miolini/go,mwhudson/go,nawawi/go,binarycrusader/go,sndnvaps/go,roth1002/go,cloudflare/go,roth1002/go,roth1002/go,derekmarcotte/go,gdey/go,binarycrusader/go,cloudflare/go,gdey/go,sndnvaps/go,linux-on-ibm-z/go,suncycheng/go,ganboing/go-esx,theif519/go,rachtsingh/gogojuice,momchil-velikov/go,roth1002/go,roth1002/go,ganboing/go-esx,Samurais/go,mwhudson/go,vanloswang/go,nawawi/go,polyverse-security/go,odeke-em/go,4ad/go,goodlang/good,Cofyc/go,Samurais/go,Jordanzuo/go,mwhudson/go,goodlang/good,vanloswang/go,cyberroadie/go,codestation/go,josharian/go,ganboing/go-esx,binarycrusader/go,goodlang/good,fjballest/golang,CAFxX/go,binarycrusader/go,4ad/go,golang/go,vsekhar/elastic-go,josharian/go,nawawi/go,polyverse-security/go,polyverse-security/go,roth1002/go,4ad/go,gdey/go,miolini/go,Cofyc/go,linux-on-ibm-z/go,rachtsingh/gogojuice,goodlang/good,mwhudson/go,polyverse-security/go,ganboing/go-esx,ganboing/go-esx,Samurais/go,Jordanzuo/go,gdey/go,vsekhar/elastic-go,golang/go,roth1002/go,suncycheng/go,akutz/go,nawawi/go,deft-code/go,vsekhar/elastic-go