add absolute links for source locations

[oliverrahner]

Proposed changes

Implements the change proposed in #7960 (closes #7960)

Checklist

• [X] Lint and unit tests pass locally with my changes.
• [X] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added documentation to describe my feature.
• [X] I have squashed my commits into logic units.
• [X] I have described the changes in the commit messages.

Other information

[codecov[bot]]

Codecov Report

Merging #7967 (7cb4ef1) into main (34fc99c) will decrease coverage by 0.00%. The diff coverage is 85.71%.

@@            Coverage Diff             @@
##             main    #7967      +/-   ##
==========================================
- Coverage   90.83%   90.82%   -0.01%     
==========================================
  Files         679      679              
  Lines       50442    50457      +15     
  Branches     7798     7800       +2     
==========================================
+ Hits        45817    45828      +11     
- Misses       3249     3252       +3     
- Partials     1376     1377       +1     

Impacted Files	Coverage Δ
weblate/trans/templatetags/translations.py	89.34% <66.66%> (+0.03%)	:arrow_up:
weblate/trans/tests/test_templatetags.py	100.00% <100.00%> (ø)
weblate/machinery/saptranslationhub.py	86.84% <0.00%> (-4.59%)	:arrow_down:
weblate/utils/checks.py	65.40% <0.00%> (-0.56%)	:arrow_down:
weblate/wladmin/views.py	67.07% <0.00%> (ø)
weblate/trans/forms.py	87.62% <0.00%> (+0.01%)	:arrow_up:
weblate/utils/stats.py	91.49% <0.00%> (+0.02%)	:arrow_up:
weblate/machinery/forms.py	68.18% <0.00%> (+0.48%)	:arrow_up:

[nijel]

Merged, thanks for your contribution!