Merge the following from the English version:

1.41 -> 1.42 books/handbook/desktop/chapter.sgml
1.102 -> 1.103 books/handbook/introduction/chapter.sgml
1.362 -> 1.366 books/handbook/mirrors/chapter.sgml
1.247 -> 1.249 books/handbook/pgpkeys/chapter.sgml

Submitted by: Ryusuke Suzuki <ryusuke at nucl dot sci dot hokudai dot ac dot jp>
Reviewed by: Hiroo Ono <hiroo at oikumene dot gcd dot org>

References: [doc-jp-work 985, 986, 988]