message: docs: add Symmetrics to users list
  * Add Symmetrics
  Symmetrics provides intelligent metrics to help make connections and matches among job seekers, recruiters, staffers and employers
  * Remove trailing space after heading
diff: @@ -137,6 +137,9 @@ Join our growing community!
  - [TrustMedis](https://trustmedis.com) [@famasya]
  - [WeSure](https://www.wesure.cn/)
  +### HR / Staffing
  +- [Symmetrics](https://www.symmetrics.fyi)
  +
  ### Others
  - [Grassroot](https://www.grassrootinstitute.org/)
  - [komoot](https://www.komoot.com/) [@christophlingg]
  