i3-nagbar: add page (#17866)

Author: acuteenvy

pages/common/i3-nagbar.md

@@ -0,0 +1,28 @@
+# i3-nagbar
+
+> Display an error/warning in a bar on top of a screen.
+> More information: <https://manned.org/i3-nagbar>.
+
+- Display an error:
+
+`i3-nagbar {{[-m|--message]}} "{{error message}}"`
+
+- Display a warning:
+
+`i3-nagbar {{[-t|--type]}} warning {{[-m|--message]}} "{{warning message}}"`
+
+- Use the specified font:
+
+`i3-nagbar {{[-f|--font]}} "{{pango:monospace bold 9}}" {{[-m|--message]}} "{{error message}}"`
+
+- Create a button and run a command in a terminal on click:
+
+`i3-nagbar {{[-b|--button]}} "{{button text}}" {{command}} {{[-m|--message]}} "{{error message}}"`
+
+- Create a button and run a command on click:
+
+`i3-nagbar {{[-B|--button-no-terminal]}} "{{button text}}" {{command}} {{[-m|--message]}} "{{error message}}"`
+
+- Always open `i3-nagbar` on the primary monitor (default: focused monitor):
+
+`i3-nagbar {{[-pm|--primary --message]}} "{{error message}}"`