Update cheatsheets

tldr/linux/systemctl-is-active

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+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# systemctl is-active
+
+> Check if one or more systemd units are active.
+> More information: <https://www.freedesktop.org/software/systemd/man/latest/systemctl.html#is-active%20PATTERN%E2%80%A6>.
+
+- Check whether a unit is active:
+
+`systemctl is-active {{unit}}`
+
+- Check whether multiple units are active:
+
+`systemctl is-active {{unit1 unit2 ...}}`
+
+- Check whether a unit is active without printing the state to `stdout`:
+
+`systemctl is-active {{[-q|--quiet]}} {{unit}}`
+
+- Check whether a user unit is active:
+
+`systemctl is-active --user {{unit}}`