test: add case for script with custom message

testdata/features/checks.feature

@@ -3,6 +3,7 @@ Feature: Checks
  When I test "checks/Script"
  Then the output should contain exactly:
  """
+ test.md:4:19:Scripts.CustomMsg:Some message
  test.md:29:1:Checks.ScriptRE:Consider inserting a new section heading at this point.
  test.md:39:1:Checks.ScriptRE:Consider inserting a new section heading at this point.
  """

testdata/fixtures/checks/Script/.vale.ini

@@ -1,4 +1,5 @@
 StylesPath = ../../../styles/
 
 [*.md]
-Checks.ScriptRE = YES
+Checks.ScriptRE = YES
+Scripts.CustomMsg = YES

testdata/styles/Scripts/CustomMsg.yml

@@ -0,0 +1,18 @@
+extends: script
+message: "Consider inserting a new section heading at this point."
+link: https://tengolang.com/
+# The unprocessed file contents.
+#
+# We need this to access heading markup.
+scope: raw
+script: |
+ text := import("text")
+
+ matches := []
+ p_limit := 3 // at most 3 paragraphs per section
+
+ // Remove all instances of code blocks since we don't want to count
+ // inter-block newlines as a new paragraph.
+ document := text.re_replace("(?s) *(\n```.*?```\n)", scope, "")
+
+ matches = append(matches, {begin: 1, end: 2, message: "Some message"})