Remove several mentions of old Python versions that don't apply anymore.
diff --git a/Lib/pdb.py b/Lib/pdb.py
index f5bdb20..bd51c31 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -909,12 +909,7 @@
With a space separated list of breakpoint numbers, clear
those breakpoints. Without argument, clear all breaks (but
first ask confirmation). With a filename:lineno argument,
-clear all breaks at that line in that file.
-
-Note that the argument is different from previous versions of
-the debugger (in python distributions 1.5.1 and before) where
-a linenumber was used instead of either filename:lineno or
-breakpoint numbers.""", file=self.stdout)
+clear all breaks at that line in that file.""", file=self.stdout)
def help_tbreak(self):
print("""tbreak same arguments as break, but breakpoint is