Add prepend command documentation

docs/commands/prepend.md

@@ -0,0 +1,56 @@
+# prepend
+This command prepends the given row to the front of the table
+
+**Note**: 
+- `prepend` does not change a file itself. If you want to save your changes, you need to run the `save` command
+- if you want to add something containing a whitespace character, you need to put it in quotation marks
+
+## Examples
+
+Let's complete this table with the missing continents:
+
+```shell
+> open continents.txt | lines
+━━━┯━━━━━━━━━━━━━━━
+ # │ <value>
+───┼───────────────
+ 0 │ Africa
+ 1 │ South America
+ 2 │ Australia
+ 3 │ Europe
+ 4 │ Antarctica
+━━━┷━━━━━━━━━━━━━━━
+```
+
+You can add a new row at the top by using `prepend`:
+
+```shell
+> open continents.txt | lines | prepend Asia
+━━━┯━━━━━━━━━━━━━━━
+ # │ <value>
+───┼───────────────
+ 0 │ Asia
+ 1 │ Africa
+ 2 │ South America
+ 3 │ Australia
+ 4 │ Europe
+ 5 │ Antarctica
+━━━┷━━━━━━━━━━━━━━━
+```
+
+It's not possible to add multiple rows at once, so you'll need to call `prepend` multiple times:
+
+```shell
+> open continents.txt | lines | prepend Asia | prepend "North America"
+━━━┯━━━━━━━━━━━━━━━
+ # │ <value>
+───┼───────────────
+ 0 │ North America
+ 1 │ Asia
+ 2 │ Africa
+ 3 │ South America
+ 4 │ Australia
+ 5 │ Europe
+ 6 │ Antarctica
+━━━┷━━━━━━━━━━━━━━━
+```