Add myself as a codeowner for the C API documentation (python#145017)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: 2 people

.github/CODEOWNERS

@@ -111,6 +111,7 @@ Doc/tools/                    @AA-Turner @hugovk
 .readthedocs.yml              @AA-Turner
 
 # Sections
+Doc/c-api/                    @ZeroIntensity
 Doc/reference/                @willingc @AA-Turner
 Doc/whatsnew/                 @AA-Turner