Add documentation for -Xtrace:maxstringlength option

[h3110n3rv3]

Issue or pull request number:
*eclipse-openj9/openj9#16416
*eclipse-openj9/openj9#20662

Overview:
Adding cmdline option to specify string argument and return value length

Release target:
Eclipse OpenJ9 0.51

Applies to the following JDK versions:
All

Applies to the following platforms:
All

For new command line options:

• Option name and syntax: -Xtrace:maxstringlength=[0-128]
• If values are set:
  • Units for setting: number of characters
  • Range: 0-128
  • Default value: If unspecified, default to 32 characters. If maxstringlength=0, prints string address.
• Purpose: Sets the string length for arguments and return values printed with -Xtrace

[Sreekala-Gopakumar]

Which release are we targeting for documenting this?

[pshipton]

0.51 / 25_02