Manpages: Auto-generate many through ArgsParser

This set was hand-curated, guided by the questions:
- Does it have at least three options, i.e. is the help page
  non-trivial?
- Is the program unusual, i.e. does listing it in Help or on
  man.serenityos.org spread awareness?
- Is the program common, but we only implement a subset of 'common'
  flags?

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

@@ -0,0 +1,25 @@
+## Name
+
+nl
+
+## Synopsis
+
+```sh
+$ nl [--body-numbering style] [--increment number] [--separator string] [--startnum number] [--width number] [file...]
+```
+
+## Options:
+
+* `--help`: Display help message and exit
+* `--version`: Print version
+* `-b style`, `--body-numbering style`: Line numbering style: 't' for non-empty lines, 'a' for all lines, 'n' for no lines
+* `-i number`, `--increment number`: Line count increment
+* `-s string`, `--separator string`: Separator between line numbers and lines
+* `-v number`, `--startnum number`: Initial line number
+* `-w number`, `--width number`: Number width
+
+## Arguments:
+
+* `file`: Files to process
+
+<!-- Auto-generated through ArgsParser -->