general: Reformat documentation with better formatting and wording

General purpose reformating and rewording in (a few places). This should
also make markdown linting happier.

Prefer back-ticks wherever useful and use `console` for code blocks to
be executed on terminal.

Also, update references links wherever possible (including update from
'http://' to 'https://').

modules/dpkg/README.md

@@ -1,10 +1,8 @@
-Dpkg
-====
+# Dpkg
 
-Defines [dpkg][1] aliases and functions.
+Defines [*dpkg*][1] aliases and functions.
 
-Aliases
--------
+## Aliases
 
 - `debc` cleans the cache.
 - `debf` displays a file's package.
@@ -20,22 +18,20 @@ Aliases
 - `deb-kclean` removes all kernel images and headers, except for the ones in
   use.
 
-Functions
----------
+## Functions
 
-- `deb-clone` generates a script that can be used to duplicate a dpkg-based
+- `deb-clone` generates a script that can be used to duplicate a `dpkg`-based
   system.
-- `deb-history` displays dpkg history.
-- `deb-kbuild` makes a dpkg Linux kernel package.
+- `deb-history` displays `dpkg` history.
+- `deb-kbuild` makes a `dpkg` Linux kernel package.
 
-Authors
--------
+## Authors
 
 *The authors of this module should be contacted via the [issue tracker][2].*
 
-  - [Daniel Bolton](https://github.com/dbb)
-  - [Benjamin Boudreau](https://github.com/dreur)
-  - [Sorin Ionescu](https://github.com/sorin-ionescu)
+- [Daniel Bolton](https://github.com/dbb)
+- [Benjamin Boudreau](https://github.com/dreur)
+- [Sorin Ionescu](https://github.com/sorin-ionescu)
 
-[1]: http://wiki.debian.org/Teams/Dpkg
+[1]: https://wiki.debian.org/Teams/Dpkg
 [2]: https://github.com/sorin-ionescu/prezto/issues