Fixes venv notations for web build

2) Removes venv notation from web bundling directions
3) Add venv notation after activation

---------
Co-authored-by: Allen Hernandez <2349718+AllenSH12@users.noreply.github.com>

README.md

@@ -42,9 +42,9 @@ installed. Then, you can run the following commands on a *nix system to
 download the required packages and build the bundle:
 
 ```bash
-(venv) $ cd $PGADMIN4_SRC
-(venv) $ make install-node
-(venv) $ make bundle
+$ cd $PGADMIN4_SRC
+$ make install-node
+$ make bundle
 ```
 
 On Windows systems (where "make" is not available), the following commands
@@ -81,7 +81,7 @@ simple - adapt as required for your distribution:
    so update that to the latest:
 
    ```bash
-   $ pip install --upgrade pip
+   (venv) $ pip install --upgrade pip
    ```
 
 4. Ensure that a PostgreSQL installation's bin/ directory is in the path (so