Bear: fail_msg -> err

We shouldn't have a logging API different than the one from the
LogPrinter.

coalib/bears/Bear.py

@@ -18,9 +18,9 @@ class Bear:
     will probably want to look at the GlobalBear and LocalBear classes that
     inherit from this class. In any case you'll want to overwrite at least the
     run method. You can send debug/warning/error messages through the
-    debug(), warn(), fail_msg() functions. These will send the
+    debug(), warn(), err() functions. These will send the
     appropriate messages so that they are outputted. Be aware that if you use
-    fail_msg(), you are expected to also terminate the bear run-through
+    err(), you are expected to also terminate the bear run-through
     immediately.
 
     If you need some setup or teardown for your bear, feel free to overwrite
@@ -60,7 +60,7 @@ def debug(self, *args, delimiter=' '):
     def warn(self, *args, delimiter=' '):
         self.__send_msg(LOG_LEVEL.WARNING, delimiter, *args)
 
-    def fail_msg(self, *args, delimiter=' '):
+    def err(self, *args, delimiter=' '):
         self.__send_msg(LOG_LEVEL.ERROR, delimiter, *args)
 
     def __send_msg(self, log_level, delimiter, *args):

coalib/tests/bears/BearTest.py

@@ -19,8 +19,8 @@ def set_up(self):
         self.debug("set", "up", delimiter="=")
 
     def tear_down(self):
-        self.fail_msg("teardown")
-        self.fail_msg()
+        self.err("teardown")
+        self.err()
 
     def run(self):
         self.warn(_("A string to test translations."))

doc/Getting_Involved/Writing_Bears.md

@@ -55,7 +55,7 @@ find it. We can do that with the `-d` (`--bear-dirs`) argument:
 
 You should now see the debug message for our sample file.
 
-The Bear class also supports `warn` and `fail_msg`.
+The Bear class also supports `warn` and `err`.
 
 ## Communicating with the User