Man: Add a manpage for rev(1)

Author: https://github.com/Mango0x45
Commit: https://github.com/SerenityOS/serenity/commit/16359429519
Pull-request: https://github.com/SerenityOS/serenity/pull/6769

Base/usr/share/man/man1/rev.md

@@ -0,0 +1,41 @@
+## Name
+
+rev - reverse lines
+
+## Synopsis
+
+```*sh
+$ rev [files...]
+```
+
+## Description
+
+`rev` reads the specified files line by line, and prints them to standard
+output with each line being reversed characterwise. If no files are specifed,
+then `rev` will read from standard input.
+
+## Examples
+
+To print two files 'foo' and 'bar' in reverse:
+```sh
+$ cat foo bar
+foo 1
+foo 2
+bar 1
+bar 2
+$ rev foo bar
+1 oof
+2 oof
+1 rab
+2 rab
+```
+
+To list files with their names in reverse:
+```sh
+$ ls
+foo
+bar
+$ ls | rev
+oof
+rab
+```