format code with gofumpt

gofumpt (https://github.com/mvdan/gofumpt) provides a supserset of `gofmt` / `go fmt`,
and addresses various formatting issues that linters may be checking for.

We can consider enabling the `gofumpt` linter to verify the formatting in CI, although
not every developer may have it installed, so for now this runs it once to get formatting
in shape.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

reference/fuzz.go

@@ -1,3 +1,4 @@
+//go:build gofuzz
 // +build gofuzz
 
 package reference

reference/normalize_test.go

@@ -84,7 +84,7 @@ func TestValidateRemoteName(t *testing.T) {
 		// Allow multiple hyphens as well.
 		"docker---rules/docker",
 
-		//Username doc and image name docker being tested.
+		// Username doc and image name docker being tested.
 		"doc/docker",
 
 		// single character names are now allowed.
@@ -129,7 +129,7 @@ func TestValidateRemoteName(t *testing.T) {
 		// No repository.
 		"docker/",
 
-		//namespace too long
+		// namespace too long
 		"this_is_not_a_valid_namespace_because_its_lenth_is_greater_than_255_this_is_not_a_valid_namespace_because_its_lenth_is_greater_than_255_this_is_not_a_valid_namespace_because_its_lenth_is_greater_than_255_this_is_not_a_valid_namespace_because_its_lenth_is_greater_than_255/docker",
 	}
 	for _, repositoryName := range invalidRepositoryNames {

reference/reference.go

@@ -3,7 +3,7 @@
 //
 // Grammar
 //
-// 	reference                       := name [ ":" tag ] [ "@" digest ]
+//	reference                       := name [ ":" tag ] [ "@" digest ]
 //	name                            := [domain '/'] path-component ['/' path-component]*
 //	domain                          := host [':' port-number]
 //	host                            := domain-name | IPv4address | \[ IPv6address \]	; rfc3986 appendix-A
@@ -11,7 +11,7 @@
 //	domain-component                := /([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9])/
 //	port-number                     := /[0-9]+/
 //	path-component                  := alpha-numeric [separator alpha-numeric]*
-// 	alpha-numeric                   := /[a-z0-9]+/
+//	alpha-numeric                   := /[a-z0-9]+/
 //	separator                       := /[_.]|__|[-]*/
 //
 //	tag                             := /[\w][\w.-]{0,127}/

reference/regexp_test.go

@@ -525,7 +525,6 @@ func TestReferenceRegexp(t *testing.T) {
 	for i := range testcases {
 		checkRegexp(t, ReferenceRegexp, testcases[i])
 	}
-
 }
 
 func TestIdentifierRegexp(t *testing.T) {