cmd/go: fix spelling error

Change-Id: Ib29da1ad77c9a243a623d25113c6f8dd0261f42a
Reviewed-on: https://go-review.googlesource.com/c/go/+/205601Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/cmd/go/internal/modload/init.go

@@ -441,7 +441,7 @@ func InitMod() {
 // fixVersion returns a modfile.VersionFixer implemented using the Query function.
 //
 // It resolves commit hashes and branch names to versions,
-// canonicalizes verisons that appeared in early vgo drafts,
+// canonicalizes versions that appeared in early vgo drafts,
 // and does nothing for versions that already appear to be canonical.
 //
 // The VersionFixer sets 'fixed' if it ever returns a non-canonical version.