all: fix spelling mistakes

src/bufio/bufio.go

@@ -425,7 +425,7 @@ func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error) {
 // of bytes in the combined first two elements, error).
 // The complete result is equal to
 // `bytes.Join(append(fullBuffers, finalFragment), nil)`, which has a
-// length of `totalLen`. The result is strucured in this way to allow callers
+// length of `totalLen`. The result is structured in this way to allow callers
 // to minimize allocations and copies.
 func (b *Reader) collectFragments(delim byte) (fullBuffers [][]byte, finalFragment []byte, totalLen int, err error) {
 	var frag []byte

src/net/http/client.go

@@ -321,7 +321,7 @@ func knownRoundTripperImpl(rt RoundTripper, req *Request) bool {
 		return true
 	}
 	// There's a very minor chance of a false positive with this.
-	// Insted of detecting our golang.org/x/net/http2.Transport,
+	// Instead of detecting our golang.org/x/net/http2.Transport,
 	// it might detect a Transport type in a different http2
 	// package. But I know of none, and the only problem would be
 	// some temporarily leaked goroutines if the transport didn't

src/runtime/mheap.go

@@ -42,7 +42,7 @@ const (
 	// roughly 100µs.
 	//
 	// Must be a multiple of the pageInUse bitmap element size and
-	// must also evenly divid pagesPerArena.
+	// must also evenly divide pagesPerArena.
 	pagesPerReclaimerChunk = 512
 
 	// go115NewMCentralImpl is a feature flag for the new mcentral implementation.