cmdline/listopts.md: update the numbers

And remove info about pre 7.73.0 curl.

cmdline/listopts.md

@@ -1,8 +1,8 @@
 # List options
 
-curl has more than two hundred command-line options and the number of options
-keep increasing over time. Chances are the number of options will reach 250
-within a few years.
+curl has more than two hundred and fifty command-line options and the number
+of options keep increasing over time. Chances are the number of options will
+reach three hundred in the coming years.
 
 To find out which options you need to perform as certain action, you can get
 curl to list them. First, `curl --help` or simply `curl -h` will get you a
@@ -11,10 +11,6 @@ an additional "category" to `-h` to get more options listed for that specific
 area. Use `curl -h category` to list all existing categories or `curl -h all`
 to list *all* available options.
 
-Before curl 7.73.0, the help category system did not exist and then `curl
---help` or simply `curl -h` would simply list all existing options in
-alphabetical order with a brief explanation next to each.
-
 The `curl --manual` option outputs the entire man page for curl. That is a
 thorough and complete document on how each option works amassing several
 thousand lines of documentation. To wade through that is also a tedious work