I really don't know why, but there is no macro (record/playback) component included in gedit, and if you are used to that as I am from Notepad++ it's hard not to cry if you come to source you need to reformat or change....
But there is a plugin for gnome2 that Eduardo Romero changed to work in gnome3. Here the (very few) steps you need to get this plugin working on your gnome3 desktop
- get the files "macropy.plugin" and "macropy.py" from https://github.com/eguaio/gedit-macropy
- copy them to /usr/lib/gedit/plugins
- restart gedit
- activate plugin in Edit/Preferences/Plugins
If you prefer to not configure the plugin for global use then you can also do it per user following the README included in the github
You are done, have fun!