Switch the default ABI on with-generated-files

Fixes #352

scripts/write-generated-grammar.sh

@@ -19,12 +19,13 @@ git reset HEAD@{1}
 npm install
 npm run test-ci
 
-# Now that we know the parser works, build for ABI 14 (but don't use this as the default because
-# it's not compatible everywhere).
+# Now that we know the parser works generate grammar files explicitly for each relatively recent ABI. Although there are
+# no known use cases that still depend on ABI 13, it does no harm to keep it around in case such a use case exists.
+npx tree-sitter generate --abi 13
 mv src/parser.c src/parser_abi13.c
 npx tree-sitter generate --abi 14
-mv src/parser.c src/parser_abi14.c
-mv src/parser_abi13.c src/parser.c
+# Leave the ABI 14 parser in place as the default, since it gives significant speed improvements over ABI 13.
+cp src/parser.c src/parser_abi14.c
 
 # Commit specific generated files, attributing the changes to the primary maintainer of this
 # grammar. Notably, we do not commit the `.o` files generated during the build, just the source.