Scale height by sex when generating related slaves

Very simple implementation of height scaling by sex for generateRelatedSlave, using the same male/female ratio of 1.07:1 as in generateGenetics. I think generateRelatedSlave is going to need an extra fuzzing pass at some point, since it seems like a lot of stats still wind up identical between relatives instead of closely similar, but I'm not going to tackle that here.

Merge Checklist

• I have read CONTRIBUTING.md
  • and
    • my code editor has
      • ESLint support enabled
      • TypeScript support enabled
      • some form of spell checker
        • We suggest using a spell checker compatible with cSpell if possible
    • my changes compile successfully and seem to work properly
    • I am using the simple compiler (simple-compiler.[bat or sh])
    • I am using the normal compiler (compile.[bat or sh])
    • this is my first merge request
    • the changes in this merge request comply with the coding style defined in CONTRIBUTING.md

Changes made

• When generating an opposite-sex relative, the changeSexTo functions now multiply or divide natural height by 1.07 as appropriate.

Things left to do

• code review (this is done by one or more people other than you)
• final tests
• let Pregmodder know that this is ready for merging