rule: rename GetAttrComments -> AttrComments (#1703)

Change the name to be more consistent with the rest of the codebase as
request in
#1700 (comment)

rule/rule.go

@@ -957,9 +957,9 @@ func (r *Rule) SetAttr(key string, value interface{}) {
 	r.updated = true
 }
 
-// GetAttrComments returns the comments for an attribute.
+// AttrComments returns the comments for an attribute.
 // It can be used to attach comments like "do not sort".
-func (r *Rule) GetAttrComments(key string) *bzl.Comments {
+func (r *Rule) AttrComments(key string) *bzl.Comments {
 	attr, ok := r.attrs[key]
 	if !ok {
 		return nil

rule/rule_test.go

@@ -609,7 +609,7 @@ func TestAttributeComment(t *testing.T) {
 	r := NewRule("a_rule", "name1")
 	r.SetAttr("deps", []string{"foo", "bar", "baz"})
 	r.SetAttr("hdrs", []string{"foo", "bar", "baz"})
-	hdrComments := r.GetAttrComments("hdrs")
+	hdrComments := r.AttrComments("hdrs")
 	hdrComments.Before = append(hdrComments.Before, bzl.Comment{
 		Token: "# do not sort",
 	})