add new TemplateEncodingError

lib/liquid/errors.rb

@@ -55,4 +55,5 @@ module Liquid
   MethodOverrideError   = Class.new(Error)
   DisabledError         = Class.new(Error)
   InternalError         = Class.new(Error)
+  TemplateEncodingError = Class.new(Error)
 end

lib/liquid/template.rb

@@ -109,7 +109,7 @@ module Liquid
       parse_context = configure_options(options)
 
       unless source.valid_encoding?
-        raise SyntaxError, parse_context.locale.t("errors.syntax.invalid_template_encoding")
+        raise TemplateEncodingError, parse_context.locale.t("errors.syntax.invalid_template_encoding")
       end
 
       tokenizer     = parse_context.new_tokenizer(source, start_line_number: @line_numbers && 1)

test/integration/template_test.rb

@@ -339,7 +339,7 @@ class TemplateTest < Minitest::Test
   end
 
   def test_raises_error_with_invalid_utf8
-    e = assert_raises(SyntaxError) do
+    e = assert_raises(TemplateEncodingError) do
       Template.parse(<<~LIQUID)
         {% comment %}
           \xC0
@@ -347,6 +347,6 @@ class TemplateTest < Minitest::Test
       LIQUID
     end
 
-    assert_equal('Liquid syntax error: Invalid template encoding', e.message)
+    assert_equal('Liquid error: Invalid template encoding', e.message)
   end
 end