Use CDATA for some manual examples

[fingolfin]

This demonstrates the use of CDATA as mentioned in PR #8. Ideally all examples would use it, also those which wrap an Include statement, but that's a much bigger change -- one either needs to move the <Example> tags into the included file, or else replace the include statements by the actual file content. Both can be done, the question is, what do you want.

[codecov]

Codecov Report

Merging #12 (dba3a4b) into master (54a3cc4) will decrease coverage by 15.02%.
The diff coverage is 32.51%.

❗ Current head dba3a4b differs from pull request most recent head 4dc4847. Consider uploading reports for the commit 4dc4847 to get more accurate results

@@             Coverage Diff             @@
##           master      #12       +/-   ##
===========================================
- Coverage   67.87%   52.84%   -15.03%     
===========================================
  Files           4        3        -1     
  Lines        2991     2772      -219     
===========================================
- Hits         2030     1465      -565     
- Misses        961     1307      +346     

Impacted Files	Coverage Δ
lib/classic.gi	14.06% <14.06%> (ø)
lib/forms.gi	53.56% <63.94%> (-9.17%)	⬇️
lib/recognition.gi	76.85% <92.68%> (-2.18%)	⬇️
lib/forms.gd
lib/recognition.gd

[fingolfin]

@jdebeule I think this PR is safe to merge. Any objections / concerns?