Update cheatsheets

tldr/linux/dnf-clean

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+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# dnf clean
+
+> Perform cleanup of temporary files kept for Red Hat-based repositories.
+> More information: <https://dnf.readthedocs.io/en/latest/command_ref.html#clean-command>.
+
+- Remove cache files generated from the repository metadata:
+
+`dnf clean dbcache`
+
+- Mark the repository metadata as expired:
+
+`dnf clean expire-cache`
+
+- Remove repository metadata:
+
+`dnf clean metadata`
+
+- Remove any cached packages from the system:
+
+`dnf clean packages`
+
+- Clean up all DNF repository specific metadata and cached files (all of the above):
+
+`dnf clean all`

tldr/linux/systemctl-cancel

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+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# systemctl cancel
+
+> Cancel one or more pending jobs in the system manager or user manager.
+> More information: <https://www.freedesktop.org/software/systemd/man/systemctl.html#cancel%20JOB%E2%80%A6>.
+
+- Cancel a job by its numeric ID:
+
+`systemctl cancel {{job_id}}`
+
+- Cancel multiple jobs:
+
+`systemctl cancel {{job_id1 job_id2 ...}}`
+
+- Cancel all pending jobs:
+
+`systemctl cancel`
+
+- Cancel a job in the user service manager:
+
+`systemctl --user cancel {{job_id}}`