vhdl: remove accidental hir doc tests
The HIR module contains BNF grammar for certain constructs which is marked as
`ignore`. This causes `cargo test` to treat them as an ignored test, rather than
as plain text. Change the `ignore` to `text` to fix the issue.
@@ -159,7 +159,7 @@ pub struct SubtypeInd {
///
/// See IEEE 1076-2008 section 6.3.
///
-/// ```ignore
+/// ```text
/// constraint := range_constraint | array_constraint | record_constraint
/// ```
#[derive(Debug)]
@@ -188,7 +188,7 @@ impl From<RecordConstraint> for Constraint {
///
/// See IEEE 1076-2008 section 6.3.
///
-/// ```ignore
+/// ```text
/// element_constraint := array_constraint | record_constraint
/// ```
#[derive(Debug)]
@@ -222,7 +222,7 @@ impl From<RecordConstraint> for ElementConstraint {
///
/// See IEEE 1076-2008 section 5.3.2.
///
-/// ```ignore
+/// ```text
/// array_constraint :=
/// index_constraint [array.element_constraint] |
/// "(" "open" ")" [array.element_constraint]
@@ -248,7 +248,7 @@ impl HasSpan for ArrayConstraint {
///
/// See IEEE 1076-2008 section 5.3.2.1.
///
-/// ```ignore
+/// ```text
/// discrete_range := discrete.subtype_indication | range
/// ```
#[derive(Debug)]
@@ -275,7 +275,7 @@ impl From<Range> for DiscreteRange {
///
/// See IEEE 1076-2008 section 5.2.1.
///
-/// ```ignore
+/// ```text
/// range := range.attribute_name | simple_expression direction simple_expression
/// ```
#[derive(Debug)]
