feat: add support for links in documentation

[princjef]

Adds support for standard and documentation links in documentation. To make this feasible, header links were changed to use explicit anchor tags and templates were rearranged.

[codecov-commenter]

Codecov Report

Merging #89 (c6b6c02) into master (7d0c2ca) will decrease coverage by 3.03%.
The diff coverage is 35.47%.

@@            Coverage Diff             @@
##           master      #89      +/-   ##
==========================================
- Coverage   61.86%   58.83%   -3.03%     
==========================================
  Files          18       20       +2     
  Lines        1563     1793     +230     
==========================================
+ Hits          967     1055      +88     
- Misses        515      655     +140     
- Partials       81       83       +2     

Impacted Files	Coverage Δ
format/devops.go	63.76% <0.00%> (-6.08%)	⬇️
format/formatcore/base.go	41.88% <0.00%> (-3.50%)	⬇️
format/github.go	60.56% <0.00%> (-5.60%)	⬇️
format/plain.go	44.44% <0.00%> (-8.89%)	⬇️
lang/block.go	0.00% <0.00%> (ø)
lang/doc.go	0.00% <0.00%> (ø)
lang/func.go	77.77% <0.00%> (-18.31%)	⬇️
lang/span.go	0.00% <0.00%> (ø)
lang/type.go	52.23% <0.00%> (-4.22%)	⬇️
lang/value.go	43.47% <0.00%> (-39.86%)	⬇️
... and 3 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.