chore: Fix markdown lint issues

.markdownlint.yaml

@@ -0,0 +1,6 @@
+MD013: false
+
+MD025: false
+
+MD007:
+  indent: 4

README.md

@@ -8,7 +8,7 @@
 Quickly extract annotations from your pdf files with the help of the [papis](https://github.com/papis/papis) bibliography manager.\
 Easily organize all your highlights and thoughts next to your documents and references.\
 
-## Installation:
+## Installation
 
 <!-- TODO set up pypi repository / explain git install path -->
 You can install through pip with `pip install git+https://git.martyoeh.me/Marty/papis-extract.git`.
@@ -24,7 +24,8 @@ You will be set up with the default options but if you want to change anything,
 
 > **Note**
 > This plugin is still in fairly early development. It does what I need it to do, but if you have a meticulously organized library *please* make backups before doing any operation which could affect your notes, or make use of the papis-included git options.
-## Usage:
+
+## Usage
 
 `papis extract [OPTIONS] [QUERY]`
 
@@ -117,6 +118,7 @@ so you will be doubling up your annotations.
 ## Configuration
 
 ### Basic configuration
+
 Add `extract` plugin settings to your papis `config` file (usually `~/.config/papis/config`):
 You will rarely have to set everything explained in the next few paragraphs -
 in fact you can use the plugin without having to set up any of it if you are happy with the defaults.