installation: fix other redirects

Somehow some of it works, some of it doesn't.
Fix them on this occasion.

Signed-off-by: Daijiro Fukuda <fukuda@clear-code.com>

Author: daipom

.gitbook.yaml

@@ -19,21 +19,21 @@ redirects:
 
   # Install
   v1.0/articles/install-by-dmg: installation/README.md
-  v1.0/articles/post-installation-guide: install/post-installation-guide.md
+  v1.0/articles/post-installation-guide: installation/post-installation-guide.md
   v1.0/articles/install-by-msi: installation/README.md
-  v1.0/articles/install-from-source: install/install-from-source.md
+  v1.0/articles/install-from-source: installation/install-from-source.md
   v1.0/articles/install-by-rpm: installation/README.md
-  v1.0/articles/before-install: install/before-install.md
-  v1.0/articles/install-by-gem: install/install-by-gem.md
+  v1.0/articles/before-install: installation/before-install.md
+  v1.0/articles/install-by-gem: installation/install-by-gem.md
   v1.0/articles/install-by-deb: installation/README.md
-  v1.0/articles/install-by-dmg-td-agent-v4: install/install-by-dmg-td-agent-v4.md
-  v1.0/articles/install-by-msi-td-agent-v4: install/install-by-msi-td-agent-v4.md
-  v1.0/articles/install-by-rpm-td-agent-v4: install/install-by-rpm-td-agent-v4.md
-  v1.0/articles/install-by-deb-td-agent-v4: install/install-by-deb-td-agent-v4.md
-  v1.0/articles/install-by-dmg-td-agent-v3: install/install-by-dmg-td-agent-v3.md
-  v1.0/articles/install-by-msi-td-agent-v3: install/install-by-msi-td-agent-v3.md
-  v1.0/articles/install-by-rpm-td-agent-v3: install/install-by-rpm-td-agent-v3.md
-  v1.0/articles/install-by-deb-td-agent-v3: install/install-by-deb-td-agent-v3.md
+  v1.0/articles/install-by-dmg-td-agent-v4: installation/install-by-dmg-td-agent-v4.md
+  v1.0/articles/install-by-msi-td-agent-v4: installation/install-by-msi-td-agent-v4.md
+  v1.0/articles/install-by-rpm-td-agent-v4: installation/install-by-rpm-td-agent-v4.md
+  v1.0/articles/install-by-deb-td-agent-v4: installation/install-by-deb-td-agent-v4.md
+  v1.0/articles/install-by-dmg-td-agent-v3: installation/install-by-dmg-td-agent-v3.md
+  v1.0/articles/install-by-msi-td-agent-v3: installation/install-by-msi-td-agent-v3.md
+  v1.0/articles/install-by-rpm-td-agent-v3: installation/install-by-rpm-td-agent-v3.md
+  v1.0/articles/install-by-deb-td-agent-v3: installation/install-by-deb-td-agent-v3.md
   installation/install-by-rpm: installation/README.md
   installation/install-by-deb: installation/README.md
   installation/install-by-msi: installation/README.md