retry-all-errors.d: Shorten the summary line

Follow-up to b995bb5 from a few moments ago.

Reported-by: Daniel Stenberg

Ref: https://github.com/curl/curl/commit/b995bb5#r39108929

docs/cmdline-opts/retry-all-errors.d

@@ -1,5 +1,5 @@
 Long: retry-all-errors
-Help: Retry all errors (use with --retry) (read manpage, don't use by default)
+Help: Retry all errors (use with --retry)
 Added: 7.71.0
 ---
 Retry on any error. This option is used together with --retry.

src/tool_help.c

@@ -400,7 +400,7 @@ static const struct helptxt helptext[] = {
   {"    --retry-delay <seconds>",
    "Wait time between retries"},
   {"    --retry-all-errors",
-   "Retry all errors (use with --retry) (read manpage, don't use by default)"},
+   "Retry all errors (use with --retry)"},
   {"    --retry-max-time <seconds>",
    "Retry only within this period"},
   {"    --sasl-authzid <identity> ",