RFR: 8354260: Launcher help text is wrong for -Xms

[Christian Stein]

Please review this update to synchronize the extra help text for `-Xms` with the description given in the manpage.

Copied from the issue:
> The launcher help text for -Xms is wrong and should be updated to match the manpage description. The actual meaning of -Xms is that it sets both the initial and minimum Java heap size, not just the initial Java heap size.
>
> ````
> $ java -X
> ...
> -Xms<size> set initial Java heap size
> ````
>
> From the manpage:
> ````
> `-Xms` *size*
> : Sets the minimum and the initial size (in bytes) of the heap. This value
>     must be a multiple of 1024 and greater than 1 MB. Append the letter `k` or
>     `K` to indicate kilobytes, `m` or `M` to indicate megabytes, or `g` or `G`
>     to indicate gigabytes. The following examples show how to set the size of
>     allocated memory to 6 MB using various units:
> ````

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Commit messages:
 - 8354260: Launcher help text is wrong for -Xms

Changes: https://git.openjdk.org/jdk/pull/25058/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25058&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354260
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25058.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25058/head:pull/25058

PR: https://git.openjdk.org/jdk/pull/25058