[doc] Update unnecessary-pass description and examples to be more s…

…pecific (pylint-dev#8877)

doc/data/messages/u/unnecessary-pass/bad.py

@@ -1,4 +1,4 @@
-class Foo:
-    """Foo docstring."""
+class DataEntryError(Exception):
+    """This exception is raised when a user has provided incorrect data."""
 
     pass  # [unnecessary-pass]

doc/data/messages/u/unnecessary-pass/good.py

@@ -1,2 +1,2 @@
-class Foo:
-    """Foo docstring."""
+class DataEntryError(Exception):
+    """This exception is raised when a user has provided incorrect data."""

doc/user_guide/checkers/features.rst

@@ -167,7 +167,8 @@ Basic checker Messages
   disable it if you're using those strings as documentation, instead of
   comments.
 :unnecessary-pass (W0107): *Unnecessary pass statement*
-  Used when a "pass" statement that can be avoided is encountered.
+  Used when a "pass" statement can be removed without affecting the behaviour
+  of the code.
 :unreachable (W0101): *Unreachable code*
   Used when there is some code behind a "return" or "raise" statement, which
   will never be accessed.

pylint/checkers/base/pass_checker.py

@@ -15,7 +15,8 @@ class PassChecker(_BasicChecker):
         "W0107": (
             "Unnecessary pass statement",
             "unnecessary-pass",
-            'Used when a "pass" statement that can be avoided is encountered.',
+            'Used when a "pass" statement can be removed without affecting '
+            "the behaviour of the code.",
         )
     }