bpo-35133: Fix mistakes when concatenate string literals on different lines. (GH-10284)

Two kind of mistakes:

1. Missed space. After concatenating there is no space between words.

2. Missed comma. Causes unintentional concatenating in a list of strings.

Lib/email/_header_value_parser.py

@@ -2209,8 +2209,8 @@ def get_section(value):
         digits += value[0]
         value = value[1:]
     if digits[0] == '0' and digits != '0':
-        section.defects.append(errors.InvalidHeaderError("section number"
+        section.defects.append(errors.InvalidHeaderError(
-            "has an invalid leading 0"))
+                "section number has an invalid leading 0"))
     section.number = int(digits)
     section.append(ValueTerminal(digits, 'digits'))
     return section, value

Lib/idlelib/idle_test/htest.py

@@ -335,7 +335,7 @@ ViewWindow_spec = {
 _widget_redirector_spec = {
     'file': 'redirector',
     'kwds': {},
-    'msg': "Every text insert should be printed to the console."
+    'msg': "Every text insert should be printed to the console "
            "or the IDLE shell."
     }
 

Lib/test/test_builtin.py

@@ -1607,7 +1607,7 @@ class TestBreakpoint(unittest.TestCase):
     @unittest.skipIf(sys.flags.ignore_environment, '-E was given')
     def test_envar_unimportable(self):
         for envar in (
-                '.', '..', '.foo', 'foo.', '.int', 'int.'
+                '.', '..', '.foo', 'foo.', '.int', 'int.',
                 'nosuchbuiltin',
                 'nosuchmodule.nosuchcallable',
                 ):

Lib/test/test_compile.py

@@ -285,7 +285,7 @@ if 1:
             'from sys import stdin)',
             'from sys import stdin, stdout,\nstderr',
             'from sys import stdin si',
-            'from sys import stdin,'
+            'from sys import stdin,',
             'from sys import (*)',
             'from sys import (stdin,, stdout, stderr)',
             'from sys import (stdin, stdout),',

Lib/test/test_http_cookiejar.py

@@ -174,12 +174,10 @@ class DateTimeTests(unittest.TestCase):
             '1980-01-01 00:61:00',
             '01-01-1980 00:00:62',
             '01-01-1980T00:00:62',
-            '19800101T250000Z'
+            '19800101T250000Z',
-            '1980-01-01 00:00:00 -2500',
             ]:
             self.assertIsNone(iso2time(test),
-                              "iso2time(%s) is not None\n"
+                              "iso2time(%r)" % test)
-                              "iso2time(test) %s" % (test, iso2time(test)))
 
 
 class HeaderTests(unittest.TestCase):

Lib/unittest/mock.py

@@ -1772,7 +1772,7 @@ _all_magics = _magics | _non_defaults
 
 _unsupported_magics = {
     '__getattr__', '__setattr__',
-    '__init__', '__new__', '__prepare__'
+    '__init__', '__new__', '__prepare__',
     '__instancecheck__', '__subclasscheck__',
     '__del__'
 }