Using a virtual environment fix (#232)

Update reference to number of steps. Consistent headers with correct heading hierarchy.

chapters/sec1/1-1-env-as-code.qmd

@@ -161,7 +161,7 @@ those purposes.
 
 ## Using a virtual environment
 
-Using a virtual environment tool is a three-step process.
+Using a virtual environment tool is a four-step process.
 
 At a high level, you'll create and use standalone package libraries, use
 tooling to capture the state of that package environment, and restore
@@ -172,7 +172,7 @@ See the cheatsheet in [Appendix @sec-append-cheat] for the exact
 commands for both R and Python.
 :::
 
-**Step 1: Create standalone package libraries**
+### Step 1: Create standalone package libraries
 
 Each project should have its own `{renv}`/`{venv}` library. When you
 start your project, it should be in a standalone directory that includes
@@ -195,7 +195,7 @@ virtual environment.
 When you work on the project, you activate the virtual environment and
 install and use packages in there.
 
-**Step 2: Document environment state**
+### Step 2: Document environment state
 
 The way to make the environment portable is to document what's in the
 package library. Both `{renv}` and `{venv}` have standard file formats
@@ -209,7 +209,7 @@ Since all this work occurs in a standalone package environment, you
 don't have to worry about what will happen if you return after a break.
 You'll still have those same packages to use.
 
-**Step 3: Collaborate or deploy**
+### Step 3: Collaborate or deploy
 
 When you go to share your project, you don't want to share your actual
 package libraries. Package installs are specific to the operating system