feature: new rules identical-switch-branches and identical-ifelseif-branches

These new rules result from the refactoring of `identical-branches` that will cover only simple/single if..else statements.

test/identical_switch_branches_test.go

@@ -0,0 +1,11 @@
+package test
+
+import (
+	"testing"
+
+	"github.com/mgechev/revive/rule"
+)
+
+func TestIdenticalSwitchBranches(t *testing.T) {
+	testRule(t, "identical_switch_branches", &rule.IdenticalSwitchBranchesRule{})
+}