autodoc: fix frontend crash while rendering std.mem

Previously we expected to only find decl refs in a `foo.bar.baz`
type of expression. This would crash when trying to render something
like `@typeInfo(T).Int.bits`. We now properly account for builtins
and other components.

lib/docs/main.js

@@ -931,8 +931,7 @@ var zigAnalysis;
             return exprName(switchIndex, opts);
           }
           case "refPath" : {
-            const declRef = expr.refPath[0].declRef;
-            let name = zigAnalysis.decls[declRef].name;
+            let name = exprName(expr.refPath[0]);
             for (let i = 1; i < expr.refPath.length; i++) {
                 let component = undefined;
                 if ("string" in expr.refPath[i]) {