feat: Adds hydronic system pressure calculator.

Sources/Styleguide/FormElements.swift

@@ -59,6 +59,17 @@ public struct Input: HTML, Sendable {
   }
 }
 
+public extension Input {
+
+  init<Key>(
+    id: Key,
+    name: String? = nil,
+    placeholder: String
+  ) where Key: RawRepresentable, Key.RawValue == String {
+    self.init(id: id.rawValue, name: name, placeholder: placeholder)
+  }
+}
+
 /// A style form input label.
 public struct InputLabel<InputLabel: HTML>: HTML {