chore: fix some typos in comments (#5243)

Signed-off-by: toofooboo <cmaker@foxmail.com>

Lib/test/test_exception_group.py

@@ -507,7 +507,7 @@ def leaf_generator(exc, tbs=None):
 
 class LeafGeneratorTest(unittest.TestCase):
     # The leaf_generator is mentioned in PEP 654 as a suggestion
-    # on how to iterate over leaf nodes of an EG. Is is also
+    # on how to iterate over leaf nodes of an EG. It is also
     # used below as a test utility. So we test it here.
 
     # TODO: RUSTPYTHON

extra_tests/custom_text_test_runner.py

@@ -217,7 +217,7 @@ class CustomTextTestResult(result.TestResult):
         self.suite_map = {}
 
     def stopTestRun(self):
-        # if no tests or some failure occured execution time may not have been set
+        # if no tests or some failure occurred execution time may not have been set
         try:
             self.results['suites'][self.suite_map[self.suite]]['execution_time'] = format(self.suite_execution_time, '.%sf' %CustomTextTestResult._execution_time_significant_digits)
         except:

extra_tests/snippets/builtin_list.py

@@ -657,7 +657,7 @@ m.list = l
 l.remove(4) 
 assert_raises(ValueError, lambda: l.index(4)) # element 4 must not be in the list
 
-# Test no panic occured when list elements was deleted in __eq__
+# Test no panic occurred when list elements was deleted in __eq__
 class rewrite_list_eq(list):
     pass
 

extra_tests/snippets/stdlib_array.py

@@ -101,7 +101,7 @@ with assert_raises(IndexError):
 
 test_str = '🌉abc🌐def🌉🌐'
 u = array('u', test_str)
-# skip as 2 bytes character enviroment with CPython is failing the test
+# skip as 2 bytes character environment with CPython is failing the test
 if u.itemsize >= 4:
     assert u.__reduce_ex__(1)[1][1] == list(test_str)
     assert loads(dumps(u, 1)) == loads(dumps(u, 3))

extra_tests/snippets/syntax_comprehension.py

@@ -43,5 +43,5 @@ assert 'c' not in globals()
 
 
 def f():
-    # Test no panic occured.
+    # Test no panic occurred.
     [[x := 1 for j in range(5)] for i in range(5)]