Add bilingual manual and localized docs routes

doc/manual/source/language/expression/literal.md

@@ -0,0 +1,20 @@
+# Literal Expression
+
+A literal expression is a concrete value written directly in source.
+
+## Kinds
+
+```dcdl
+"hello"
+123
+3.14
+true
+false
+```
+
+## Corresponding primitive types
+
+- A string literal satisfies `String`.
+- An integer literal satisfies `Int`.
+- A floating-point literal satisfies `Float`.
+- `true` and `false` satisfy `Bool`.