src: fix typos

Fix typos in ~30 files

Change-Id: Ie433aea01e7d15944c1e9e103691784876d5c1f9
GitHub-Last-Rev: bbaeb3d1f88a5fa6bbb69607b1bd075f496a7894
GitHub-Pull-Request: golang/go#68964
Reviewed-on: https://go-review.googlesource.com/c/go/+/606955
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

Author: Sajjon

src/compress/flate/huffman_code.go

@@ -176,7 +176,7 @@ func (h *huffmanEncoder) bitCounts(list []literalNode, maxBits int32) []int32 {
 	for {
 		l := &levels[level]
 		if l.nextPairFreq == math.MaxInt32 && l.nextCharFreq == math.MaxInt32 {
-			// We've run out of both leafs and pairs.
+			// We've run out of both leaves and pairs.
 			// End all calculations for this level.
 			// To make sure we never come back to this level or any lower level,
 			// set nextPairFreq impossibly large.