Fix typos, drop mentions of Python<3.6

setup.py

@@ -73,7 +73,7 @@ def read(name):
 
 if not NO_EXTENSIONS:
     print("**********************")
-    print("* Accellerated build *")
+    print("* Accelerated build *")
     print("**********************")
     setup(ext_modules=extensions, **args)
 else:

tests/test_url.py

@@ -1,21 +1,17 @@
-import sys
 import pytest
 from urllib.parse import SplitResult
 
 from yarl import URL
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 6), reason="The feature requires Python 3.6+"
-)
 def test_inheritance():
     with pytest.raises(TypeError) as ctx:
 
         class MyURL(URL):  # type: ignore[misc]
             pass
 
     assert (
-        "Inheritance a class "
+        "Inheriting a class "
         "<class 'test_url.test_inheritance.<locals>.MyURL'> "
         "from URL is forbidden" == str(ctx.value)
     )
@@ -1222,9 +1218,6 @@ def test_join_from_rfc_3986_normal(url, expected):
 ]
 
 
-@pytest.mark.skipif(
-    sys.version_info < (3, 5), reason="Python 3.4 doen't support abnormal cases"
-)
 @pytest.mark.parametrize("url,expected", ABNORMAL)
 def test_join_from_rfc_3986_abnormal(url, expected):
     # test case from https://tools.ietf.org/html/rfc3986.html#section-5.4.2

tests/test_url_parsing.py

@@ -254,7 +254,6 @@ def test_another_bad_port(self):
         with pytest.raises(ValueError):
             URL("//h:22:no/path")
 
-    @pytest.mark.skipif(sys.version_info < (3, 6), reason="Requires Python 3.6+")
     def test_bad_port_again(self):
         with pytest.raises(ValueError):
             URL("//h:-80/path")

yarl/_url.py

@@ -261,7 +261,7 @@ def build(
             return url
 
     def __init_subclass__(cls):
-        raise TypeError("Inheritance a class {!r} from URL is forbidden".format(cls))
+        raise TypeError("Inheriting a class {!r} from URL is forbidden".format(cls))
 
     def __str__(self):
         val = self._val