fix: Silence build warnings

Sources/FilterTag.swift

@@ -11,7 +11,7 @@ class FilterNode : NodeType {
 
     let blocks = try parser.parse(until(["endfilter"]))
 
-    guard let token = parser.nextToken() else {
+    guard parser.nextToken() != nil else {
       throw TemplateSyntaxError("`endfilter` was not found.")
     }
 

Sources/Template.swift

@@ -64,7 +64,7 @@ public class Template: ExpressibleByStringLiteral {
 
   /// Render the given template with a context
   func render(_ context: Context) throws -> String {
-    let context = context ?? Context(environment: environment)
+    let context = context
     let parser = TokenParser(tokens: tokens, namespace: context.namespace)
     let nodes = try parser.parse()
     return try renderNodes(nodes, context)