Allow responding to HTML when no template present

If no template present, allow the request to render the view and then
only render a 404 if the view does not redirect, otherwise all views
would need a placeholder Zmpl template even if the view does not use it.

Also parse HTTP body as query string if present.

src/jetzig/http/Request.zig

@@ -258,7 +258,8 @@ fn queryParams(self: *Self) !*jetzig.data.Value {
 }
 
 fn parseQueryString(self: *Self) !bool {
-    if (self.path.query) |query| {
+    const data: ?[]const u8 = if (self.body.len > 0) self.body else self.path.query;
+    if (data) |query| {
         self.query.* = jetzig.http.Query.init(
             self.allocator,
             query,

src/jetzig/http/Server.zig

@@ -144,12 +144,18 @@ fn renderHTML(
     route: ?*jetzig.views.Route,
 ) !void {
     if (route) |matched_route| {
-        if (zmpl.find(matched_route.template)) |template| {
-            const rendered = self.renderView(matched_route, request, template) catch |err| {
-                if (isUnhandledError(err)) return err;
-                const rendered_error = try self.renderInternalServerError(request, err);
-                return request.setResponse(rendered_error, .{});
-            };
+        const template = zmpl.find(matched_route.template);
+        if (template == null) {
+            if (try self.renderMarkdown(request, route)) |rendered_markdown| {
+                return request.setResponse(rendered_markdown, .{});
+            }
+        }
+        const rendered = self.renderView(matched_route, request, template) catch |err| {
+            if (isUnhandledError(err)) return err;
+            const rendered_error = try self.renderInternalServerError(request, err);
+            return request.setResponse(rendered_error, .{});
+        };
+        if (request.status_code != .not_found) {
             return request.setResponse(rendered, .{});
         }
     }
@@ -265,8 +271,10 @@ fn renderView(
                 .content = try self.renderTemplateWithLayout(request, capture, rendered_view, route),
             };
         } else {
-            // We are rendering JSON, content is the result of `toJson` on view data.
-            return .{ .view = rendered_view, .content = "" };
+            return switch (request.requestFormat()) {
+                .HTML, .UNKNOWN => try renderNotFound(request),
+                .JSON => .{ .view = rendered_view, .content = "" },
+            };
         }
     } else {
         try self.logger.WARN("`request.render` was not invoked. Rendering empty content.", .{});