Fix po4a.conf

Author: steveklabnik

src/doc/po4a.conf

@@ -19,7 +19,7 @@
 [type: text] src/doc/guide-tasks.md $lang:doc/l10n/$lang/guide-tasks.md
 [type: text] src/doc/guide-testing.md $lang:doc/l10n/$lang/guide-testing.md
 [type: text] src/doc/guide-unsafe.md $lang:doc/l10n/$lang/guide-unsafe.md
-[type: text] src/doc/guide-unsafe.md $lang:doc/l10n/$lang/guide-crates.md
+[type: text] src/doc/guide-crates.md $lang:doc/l10n/$lang/guide-crates.md
 [type: text] src/doc/guide.md $lang:doc/l10n/$lang/guide.md
 [type: text] src/doc/index.md $lang:doc/l10n/$lang/index.md
 [type: text] src/doc/intro.md $lang:doc/l10n/$lang/intro.md