Fix typos in comments and a test failure message (#2600)

No functional change.

docs/flaky-tests.md

@@ -28,7 +28,7 @@ processes are vying for CPU time.
   sudo cgset -r cpu.cfs_quota_us=10000 cpulimit
   sudo cgset -r cpu.cfs_period_us=1000000 cpulimit
 
-  # Run a shell with in our limited environemnt
+  # Run a shell with in our limited environment
   sudo cgexec -g cpu:cpulimit bash
 
   # In the shell, run the test

examples/libp2p-host/README.md

@@ -84,7 +84,7 @@ defer h2.Close()
 fmt.Printf("Hello World, my second hosts ID is %s\n", h2.ID())
 ```
 
-And thats it, you have a libp2p host and you're ready to start doing some awesome p2p networking!
+And that's it, you have a libp2p host and you're ready to start doing some awesome p2p networking!
 
 In future guides we will go over ways to use hosts, configure them differently (hint: there are a huge number of ways to set these up), and interesting ways to apply this technology to various applications you might want to build.
 

p2p/host/peerstore/test/peerstore_suite.go

@@ -144,7 +144,7 @@ func testGetStreamBeforePeerAdded(ps pstore.Peerstore) func(t *testing.T) {
 				t.Fatal("channel shouldnt be closed yet")
 			}
 			if a == nil {
-				t.Fatal("got a nil address, thats weird")
+				t.Fatal("got a nil address, that's weird")
 			}
 			count++
 			if received[a.String()] {
@@ -195,7 +195,7 @@ func testAddrStreamDuplicates(ps pstore.Peerstore) func(t *testing.T) {
 		var count int
 		for a := range ach {
 			if a == nil {
-				t.Fatal("got a nil address, thats weird")
+				t.Fatal("got a nil address, that's weird")
 			}
 			count++
 			if received[a.String()] {