docs(js): add code level docs

[darrenjennings]

Fixes #150

[codecov-io]

Codecov Report

Merging #183 into master will not change coverage by %.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #183   +/-   ##
=======================================
  Coverage   84.79%   84.79%           
=======================================
  Files           1        1           
  Lines         171      171           
  Branches       49       49           
=======================================
  Hits          145      145           
  Misses         11       11           
  Partials       15       15           

Impacted Files	Coverage Δ
src/Autosuggest.vue	84.79% <100.00%> (ø)

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