cmd/internal/src: fix typo in pos.go

Change-Id: I31ac8845e72c3027c9a463b1f691f4d2b7913ec0
GitHub-Last-Rev: a6b185cc41d649141e6034b77bcfe53525498ea6
GitHub-Pull-Request: golang/go#29682
Reviewed-on: https://go-review.googlesource.com/c/157518Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>

src/cmd/internal/src/pos.go

@@ -343,7 +343,7 @@ const (
 	// positions.
 	//
 	PosDefaultStmt uint = iota // Default; position is not a statement boundary, but might be if optimization removes the designated statement boundary
-	PosIsStmt                  // Position is a statement bounday; if optimization removes the corresponding instruction, it should attempt to find a new instruction to be the boundary.
+	PosIsStmt                  // Position is a statement boundary; if optimization removes the corresponding instruction, it should attempt to find a new instruction to be the boundary.
 	PosNotStmt                 // Position should not be a statement boundary, but line should be preserved for profiling and low-level debugging purposes.
 )