Apply suggestions from code review

Co-authored-by: elsdvlee <[email protected]>

Author: bjdmeest

spec/section/annotations.md

@@ -185,7 +185,7 @@ The second constraint naturally corresponds to a `FOREIGN KEY` constraint from t
 
 We can exploit the mechanism of structural annotations to inform the RML engine about the existence of such "relational-like" constraint. We here work out an example.
 
-First, we need to specify the logical sources. The logical source corresponding to the CSVof [[[#primary-key]]]:
+First, we need to specify the logical sources. The logical source corresponding to the CSV of [[[#primary-key]]]:
 
 <aside class=ex-mapping>