Improve max-errors help message, remove get_fail_after

Ref. #748

rflx/cli.py

@@ -33,7 +33,7 @@ def main(argv: List[str]) -> Union[int, str]:
         type=int,
         default=0,
         metavar=("NUM"),
-        help="Maximum number of errors to report",
+        help="exit after at most NUM errors",
     )
 
     subparsers = parser.add_subparsers(dest="subcommand")

rflx/error.py

@@ -15,12 +15,6 @@ def set_fail_after(count: int) -> None:
     FAIL_AFTER_VALUE = count
 
 
-def get_fail_after() -> int:
-    # pylint: disable = global-statement
-    global FAIL_AFTER_VALUE
-    return FAIL_AFTER_VALUE
-
-
 class Location(Base):
     def __init__(
         self,
@@ -152,17 +146,19 @@ def extend(
         self,
         entries: Union[List[Tuple[str, Subsystem, Severity, Optional[Location]]], "BaseError"],
     ) -> None:
+        # pylint: disable = global-statement
+        global FAIL_AFTER_VALUE
         if isinstance(entries, BaseError):
             self.__errors.extend(entries.errors)
         else:
             for message, subsystem, severity, location in entries:
                 self.__errors.append(BaseError.Entry(message, subsystem, severity, location))
         if (
-            get_fail_after() > 0
-            and len(
+            0
+            > FAIL_AFTER_VALUE
+            >= len(
                 list(e for e in self.__errors if e.severity in (Severity.WARNING, Severity.ERROR))
             )
-            >= get_fail_after()
         ):
             raise self