docs: Fix grammar

README.org

@@ -1,6 +1,6 @@
 * nix-org-babel
 This is an implementation of =org-babel-tangle= in Nix.
-Given an Org string, it extracts the contents of source blocks of a particular language.
+Given an Org string, it extracts the contents of source blocks in a particular language.
 ** Rationale
 [[https://github.com/talyz/fromElisp][talyz/fromElisp]] provides support for Org, and it is also part of [[https://github.com/nix-community/emacs-overlay][emacs-overlay]], which apparently is used by many people for their own configs.
 However, I wanted to experiment with more advanced features such as excluding archived entries, and I wasn't sure if I could mix that with their code base.