Remove useless relative links in problem statements about codecheck2

[cayhorstmann]

Here is an example of such a file. https://codecheck.io/files/wiley/ebook-bc-3-ch14-sec03-cc-1

There are quite a few others, with ids (after wiley/)

ebook-py-2-ch08-sec03-int1-5
ebook-py-2-ch04-sec04-int1-4
ebook-py-3-ch04-sec09-cc-1
ebook-py-3-ch06-sec05-cc-1
ebook-py-3-ch06-sec05-cc-3
ebook-py-3-ch10-sec06-cc-4
ebook-bc-3-ch16-sec02-cc-1
ebook-bc-3-ch08-sec01-cc-5
ebook-bc-3-ch08-sec02-cc-1
ebook-bc-3-ch04-sec03-cc-2
ebook-bc-3-ch04-sec02-cc-2
ebook-bc-3-ch06-sec05-cc-2
ebook-bc-3-ch06-sec05-cc-1
ebook-bc-3-ch06-sec04-cc-1
ebook-bc-3-ch06-sec04-cc-3
ebook-bc-3-ch06-sec02-cc-2
ebook-bc-3-ch06-sec07-cc-2
ebook-bc-3-ch05-sec10-cc-4
ebook-bc-3-ch05-sec07-cc-2
ebook-bc-3-ch09-sec05-cc-2
ebook-bc-3-ch09-sec04-cc-2
ebook-bc-3-ch09-sec04-cc-1
ebook-bc-3-ch09-sec02-cc-2
ebook-bc-3-ch14-sec03-cc-1
ebook-bc-3-ch02-sec04-cc-2
ebook-bjlo-2-ch06-sec05-cc-2
ebook-bjlo-2-ch06-sec05-cc-1
ebook-bjlo-2-ch10-sec04_03-int1-7
ebook-bjlo-2-ch10-sec04_03-int1-6
ebook-bjlo-2-ch07-sec04-cc-1
ebook-bjlo-2-ch03-sec07-cc-5
ebook-bjeo-7-ch16-sec02-cc-1
ebook-bjeo-7-ch04-sec04-cc-2
ebook-bjeo-7-ch04-sec04-cc-1
ebook-bjeo-7-ch05-sec07-cc-1
ebook-bjeo-7-ch11-sec04-cc-2
ebook-bjeo-7-ch03-pr2-cc-1
ebook-bjeo-6-ch04-sec04-int2-3
ebook-bjeo-6-ch05-sec02-int2-5
ebook-bjeo-6-ch07-sec07_02-int2-1
ebook-bjeo-6-ch07-sec04-int2-2
ebook-bjeo-6-ch07-sec07_05-int2-1
ebook-bjeo-6-ch03-sec08-int2-2
ebook-bjeo-6-ch03-sec08-int2-1
ebook-bjeo-6-ch03-sec08-int2-3

Have a look at the HTML and figure out what to filter out. For example,

<a class='qref' href='#ebook-bjeo-6-ch05-sec02-int2-4'>the preceding problem</a>

should become

the preceding problem

[thinh241819]

@cayhorstmann I want to try solving this issue.