The fair solution is to grep the entire codebase for 'he', 'him', and similarly gendered pronouns, and then randomly replace 50% of them with the corresponding female pronouns. This should be done regularly if desired.
Also, stuff like "using gendered language is hostile" is absolute rubbish. It is not hostile to have a specific instance of gendered language in technical documentation -- it makes it more personal and identifiable. To be fair, this identification can be randomized between male and female.
[EDIT: downvoters, how about my choice to not want to be known as "them" and suchlike? I would like my pronoun to be in the singular form. I am not multiple people.]