UPDATE: consistent CLI installation instructions

Removed the $ symbol on the few that had them, so that these commands are
a) consistent with the other ones already in the README
b) more compatible with GitHub's new feature allowing you to click the copy button on the side of a code snippet and paste to terminal without having to delete the "$"

Author: mitchazj

README.md

@@ -101,13 +101,13 @@ For use in [JupyterLab](https://jupyterlab.readthedocs.io/en/stable/), install t
 packages using `pip`:
 
 ```
-$ pip install "jupyterlab>=3" "ipywidgets>=7.6"
+pip install "jupyterlab>=3" "ipywidgets>=7.6"
 ```
 
 or `conda`:
 
 ```
-$ conda install "jupyterlab>=3" "ipywidgets>=7.6"
+conda install "jupyterlab>=3" "ipywidgets>=7.6"
 ```
 
 The instructions above apply to JupyterLab 3.x. **For JupyterLab 2 or earlier**, run the following commands to install the required JupyterLab extensions (note that this will require [`node`](https://nodejs.org/) to be installed):
@@ -147,13 +147,13 @@ The [`kaleido`](https://github.com/plotly/Kaleido) package has no dependencies a
 using pip...
 
 ```
-$ pip install -U kaleido
+pip install -U kaleido
 ```
 
 or conda.
 
 ```
-$ conda install -c conda-forge python-kaleido
+conda install -c conda-forge python-kaleido
 ```
 
 #### Orca