Fix confusing wording about installation logs

Signed-off-by: Yann Dirson <[email protected]>

Author: ydirson

docs/troubleshooting/installation-upgrade.md

@@ -64,10 +64,10 @@ On the host, run `efibootmgr`.
 
 ## Installation logs
 
-The installer writes in `/var/log/installer/`.
+On the installed system, installer logs are kept in `/var/log/installer/`.
 
 The main log file is `/var/log/installer/install-log`.
 
 ## Debugging the installer
 
-You can [build your own installer](../../project/development-process/ISO-modification).
+You can [build your own installer](../../project/development-process/ISO-modification).