diff,misspell: fix typos in comments (#282)

Author: alexandear

diff/diff.go

@@ -76,7 +76,7 @@ func Diff(oldName string, old []byte, newName string, new []byte) []byte {
 
 		// Expand matching lines as far possible,
 		// establishing that x[start.x:end.x] == y[start.y:end.y].
-		// Note that on the first (or last) iteration we may (or definitey do)
+		// Note that on the first (or last) iteration we may (or definitely do)
 		// have an empty match: start.x==end.x and start.y==end.y.
 		start := m
 		for start.x > done.x && start.y > done.y && x[start.x-1] == y[start.y-1] {

internal/misspell/misspell.go

@@ -1,4 +1,4 @@
-// Package misspell impements utilities for basic spelling correction.
+// Package misspell implements utilities for basic spelling correction.
 package misspell
 
 import (