Miscellaneous docs fixes (#378)

## Description

<!-- Provide a brief description of the PR's purpose here. -->

Misc fixes to docs.

## TODO

<!-- Notable points that this PR has either accomplished or will
accomplish. -->

- [x] Install `all` in addition to `dev` in CONTRIBUTING so that tests
pass
- [x] Fix PR format for a line in HISTORY.md

## Questions

<!-- Any concerns or points of confusion? -->

## Status

- [x] I have read the guidelines in

[CONTRIBUTING.md](https://github.com/icaros-usc/pyribs/blob/master/CONTRIBUTING.md)
- [x] I have formatted my code using `yapf`
- [x] I have tested my code by running `pytest`
- [x] I have linted my code with `pylint`
- [N/A] I have added a one-line description of my change to the
changelog in
      `HISTORY.md`
- [x] This PR is ready to go

CONTRIBUTING.md

@@ -33,9 +33,10 @@ Ready to contribute? Here's how to set up pyribs for local development.
 
    ```bash
    cd pyribs
-   conda create --prefix ./env python=3.8 # 3.8 is the minimum version pyribs supports.
+   conda create --prefix ./env python=3.8  # 3.8 is the minimum version pyribs supports.
    conda activate ./env
-   pip install -e .[dev]
+   pip install -e .[all,dev]  # `all` contains dependencies for all extras of pyribs.
+                              # `dev` contains development dependencies.
    ```
 
 1. We roughly follow the

HISTORY.md

@@ -21,7 +21,7 @@
 - **Backwards-incompatible:** Allow using kwargs for colorbar in
   parallel_axes_plot ({pr}`358`)
   - Removes cbar_orientaton and cbar_pad args for parallel_axes_plot
-- Add `rasterized` arg for heatmaps (#359)
+- Add `rasterized` arg for heatmaps ({pr}`359`)
 - Support 1D cvt_archive_heatmap ({pr}`362`)
 - Add 3D plots for CVTArchive ({pr}`371`)
 - Add visualization of 3D QDax repertoires ({pr}`373`)