Adjust html anchor to work with the fixed header

[seratch]

Summary

This pull request improves the document pages by adjusting HTML anchor positions. As a workaround, I needed to always place <hr/> in front of h2 tags to make this fix work.

Before

After

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #436 into master will decrease coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #436      +/-   ##
============================================
- Coverage     83.94%   83.88%   -0.07%     
+ Complexity     2368     2367       -1     
============================================
  Files           249      249              
  Lines          6366     6366              
  Branches        578      578              
============================================
- Hits           5344     5340       -4     
- Misses          668      672       +4     
  Partials        354      354              

Impacted Files	Coverage Δ	Complexity Δ
...pi/methods/metrics/impl/RedisMetricsDatastore.java	87.03% <0.00%> (-2.47%)	37.00% <0.00%> (-1.00%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 6b00e32...08b5ca3. Read the comment docs.