ical: add page (#5849)

pages/common/ical.md

@@ -0,0 +1,16 @@
+# ical
+
+> A Hirji/Islamic calendar and converter for the terminal.
+> More information: <https://manned.org/ical>.
+
+- Display the current month's calendar:
+
+`ical`
+
+- Convert a Gregorian date to a Hijri date:
+
+`ical --gregorian {{yyyymmdd}}`
+
+- Convert a Hirji date to a Gregorian date:
+
+`ical --hijri {{yyyymmdd}}`