gh-113317: Remove Argument Clinic global variable 'clinic'

* Add Clinic.warn() and Clinic.fail() methods.
* Add filename parameter to BlockParser constructor.
* Add BlockParser.fail() method.
* Add DSLParser.fail() method.
* Pass lineno parameter to DSLParser.format_docstring(): more
  accurate error reporting.
* Convert a few DSLParser static methods to regular method to be able
  to call self.fail().
* Language.render() clinic parameter is now required: None is no
  longer accepted.
* Remove warn() function.
* Remove global variable 'clinic'.

fail() and warn() methods get filename and line number from the
instance on which the method is called, rather than relying on a
global variable 'clinic'.

Lib/test/test_clinic.py

@@ -2390,7 +2390,7 @@ def test_state_func_docstring_no_summary(self):
             docstring1
             docstring2
         """
-        self.expect_failure(block, err, lineno=0)
+        self.expect_failure(block, err, lineno=3)
 
     def test_state_func_docstring_only_one_param_template(self):
         err = "You may not specify {parameters} more than once in a docstring!"
@@ -2404,7 +2404,7 @@ def test_state_func_docstring_only_one_param_template(self):
             these are the params again:
                 {parameters}
         """
-        self.expect_failure(block, err, lineno=0)
+        self.expect_failure(block, err, lineno=7)
 
 
 class ClinicExternalTest(TestCase):