Fix the confusing different names of fulltrace (#5668)

Fix the confusing different names of `fulltrace`

Author: nicoddemus

src/_pytest/terminal.py

@@ -692,7 +692,7 @@ def _report_keyboardinterrupt(self):
             else:
                 excrepr.reprcrash.toterminal(self._tw)
                 self._tw.line(
-                    "(to show a full traceback on KeyboardInterrupt use --fulltrace)",
+                    "(to show a full traceback on KeyboardInterrupt use --full-trace)",
                     yellow=True,
                 )
 

testing/test_terminal.py

@@ -233,7 +233,7 @@ def test_interrupt_me():
             )
         else:
             result.stdout.fnmatch_lines(
-                ["(to show a full traceback on KeyboardInterrupt use --fulltrace)"]
+                ["(to show a full traceback on KeyboardInterrupt use --full-trace)"]
             )
         result.stdout.fnmatch_lines(["*KeyboardInterrupt*"])