Documentation: Fix typo of reference file name

Fix a typo of Documentation/trace/fprobe.rst.

Link: https://lore.kernel.org/all/168584575125.2056209.5771945721143181243.stgit@mhiramat.roam.corp.google.com/

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306040144.aD72UzkF-lkp@intel.com/
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Author: mhiramat

Documentation/trace/fprobetrace.rst

@@ -38,7 +38,7 @@ Synopsis of fprobe-events
                   with a digit character, "_TRACEPOINT" is used.
  MAXACTIVE      : Maximum number of instances of the specified function that
                   can be probed simultaneously, or 0 for the default value
-                  as defined in Documentation/trace/fprobes.rst
+                  as defined in Documentation/trace/fprobe.rst
 
  FETCHARGS      : Arguments. Each probe can have up to 128 args.
   ARG           : Fetch "ARG" function argument using BTF (only for function