[lldb] Fix redundant newline in AppendError calls.

AppendError always appends a newline to the given argument, while
AppendErrorWithFormat does not. I've updated the calls to remove the
extra newline.
diff --git a/lldb/source/Breakpoint/BreakpointIDList.cpp b/lldb/source/Breakpoint/BreakpointIDList.cpp
index 95ae605..e6a5dce 100644
--- a/lldb/source/Breakpoint/BreakpointIDList.cpp
+++ b/lldb/source/Breakpoint/BreakpointIDList.cpp
@@ -223,7 +223,7 @@
       result.AppendError("Invalid breakpoint id range:  Either "
                          "both ends of range must specify"
                          " a breakpoint location, or neither can "
-                         "specify a breakpoint location.\n");
+                         "specify a breakpoint location.");
       result.SetStatus(eReturnStatusFailed);
       return;
     }