Misc docs improvements

[scarletfog]

Context

Several smaller things to improve - better wording, styling for tables, removal of the roadmap page (as requested).

How has this been tested?

I ran the documentation locally.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Related issue(s):

1. Misc improvements to the documentation (API and guide) #572

[codecov]

Codecov Report

Merging #577 (22937df) into develop (a9ee306) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #577   +/-   ##
========================================
  Coverage    92.59%   92.59%           
========================================
  Files          162      162           
  Lines        37282    37282           
  Branches      5406     5406           
========================================
  Hits         34520    34520           
  Misses        2755     2755           
  Partials         7        7           

[scarletfog]

@wojciechczerniak I need your help here with two things -

1. I could not resolve an issue we have with "help us improve this page" that leads to 404, for example: https://handsontable.github.io/hyperformula/api/ - I tried to play with frontmatter as I found this issue: Enable editLink on specific page vuejs/vuepress#1762 but without success - it's displayed just like a normal text.
2. Which file could be used to count the current number of available functions? In the config file, I saw we have HyperFormula.version, HyperFormula.buildDate, HyperFormula.releaseDate and I suspect we should add something similar: HyperFormula.functionsNumber to be later used as: {{ $page.functionsNumber }}.

[wojciechczerniak]

@scarletfog see d1f41b2

[scarletfog]

Ah, thank you so much @wojciechczerniak!

[wojciechczerniak]

Awesome! 🥇