Revisit some help texts with regard to newlines

src/_pytest/assertion/__init__.py

@@ -27,11 +27,12 @@ def pytest_addoption(parser):
         choices=("rewrite", "plain"),
         default="rewrite",
         metavar="MODE",
-        help="""Control assertion debugging tools.  'plain'
+        help=(
-                            performs no assertion debugging.  'rewrite'
+            "Control assertion debugging tools.\n"
-                            (the default) rewrites assert statements in
+            "'plain' performs no assertion debugging.\n"
-                            test modules on import to provide assert
+            "'rewrite' (the default) rewrites assert statements in test modules"
-                            expression information.""",
+            " on import to provide assert expression information."
+        ),
     )
     parser.addini(
         "enable_assertion_pass_hook",

src/_pytest/cacheprovider.py

@@ -397,9 +397,9 @@ def pytest_addoption(parser):
         "--failed-first",
         action="store_true",
         dest="failedfirst",
-        help="run all tests but run the last failures first.  "
+        help="run all tests, but run the last failures first.\n"
         "This may re-order tests and thus lead to "
-        "repeated fixture setup/teardown",
+        "repeated fixture setup/teardown.",
     )
     group.addoption(
         "--nf",

src/_pytest/helpconfig.py

@@ -57,7 +57,7 @@ def pytest_addoption(parser):
         dest="plugins",
         default=[],
         metavar="name",
-        help="early-load given plugin module name or entry point (multi-allowed). "
+        help="early-load given plugin module name or entry point (multi-allowed).\n"
         "To avoid loading of plugins, use the `no:` prefix, e.g. "
         "`no:doctest`.",
     )

src/_pytest/mark/__init__.py

@@ -79,8 +79,8 @@ def pytest_addoption(parser):
         dest="markexpr",
         default="",
         metavar="MARKEXPR",
-        help="only run tests matching given mark expression.  "
+        help="only run tests matching given mark expression.\n"
-        "example: -m 'mark1 and not mark2'.",
+        "For example: -m 'mark1 and not mark2'.",
     )
 
     group.addoption(