Remove the errant backtick in the README.rst

[rmarkello]

The issue

There is an unnecessary backtick (`) at the beginning L48 of the abagen/info.py file that is showing up in the README and should be removed:

abagen/abagen/info.py

Lines 47 to 50 in c64d948

	Arnatkevičiūte et al., 2019 provided a thorough treatment of this in a `recent
	`manuscript <https://www.sciencedirect.com/science/article/pii/
	S1053811919300114>`__, demonstrating how the techniques and code used to
	prepare the raw AHBA data have varied widely across published reports.

Proposed solution

We try not to edit the README.rst file directly, so this can be accomplished by following these steps:

1. Delete the extra backtick (the one immediately preceding the word 'manuscript') in the abagen/info.py file:

- `manuscript <https://www.sciencedirect.com/science/article/pii/ 
+ manuscript <https://www.sciencedirect.com/science/article/pii/ 

2. Regenerate the README.rst file by running bash tools/update_readme.py from the root of the abagen directory.
3. Commit the changes to both files and open a PR!

[4lovi4]

Hi @rmarkello may I take a shot to resolve the issue?