jobspec: fixup vault_grace deprecation

Followup to #7170

- Moved canonicalization of VaultGrace back into `api/` package.
- Fixed tests.
- Made docs styling consistent.

api/jobs_test.go

@@ -531,6 +531,7 @@ func TestJobs_Canonicalize(t *testing.T) {
 										LeftDelim:    stringToPtr("{{"),
 										RightDelim:   stringToPtr("}}"),
 										Envvars:      boolToPtr(false),
+										VaultGrace:   timeToPtr(0),
 									},
 									{
 										SourcePath:   stringToPtr(""),
@@ -543,6 +544,7 @@ func TestJobs_Canonicalize(t *testing.T) {
 										LeftDelim:    stringToPtr("{{"),
 										RightDelim:   stringToPtr("}}"),
 										Envvars:      boolToPtr(true),
+										VaultGrace:   timeToPtr(0),
 									},
 								},
 							},

api/tasks.go

@@ -750,6 +750,11 @@ func (tmpl *Template) Canonicalize() {
 	if tmpl.Envvars == nil {
 		tmpl.Envvars = boolToPtr(false)
 	}
+
+	//COMPAT(0.12) VaultGrace is deprecated and unused as of Vault 0.5
+	if tmpl.VaultGrace == nil {
+		tmpl.VaultGrace = timeToPtr(0)
+	}
 }
 
 type Vault struct {