Update docs for 1.3.8 release - #955

These files were overwritten during the `brew link` step:

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!

libgcrypt 1.11.2 is already installed and up-to-date. To reinstall 1.11.2, run: brew reinstall libgcrypt

gnutls 3.8.10 is already installed and up-to-date. To reinstall 3.8.10, run: brew reinstall gnutls

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!

pkgconf 2.5.1 is already installed and up-to-date. To reinstall 2.5.1, run: brew reinstall pkgconf

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!