Fix confusing wording about installation logs

Signed-off-by: Yann Dirson <yann.dirson@vates.tech>

Author: ydirson

docs/troubleshooting/installation-upgrade.md

@@ -31,10 +31,10 @@ The target installation partition is mounted in `/tmp/root`.
 
 ## Installation logs
 
-The installer writes in `/var/log/installer/`.
+On the installed system, the 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).