[man] Followup: Fix order of depot_tools in PATH in html docs

This is a followup to https://chromium-review.googlesource.com/2124657

TBR=ahaas@chromium.org, ehmaldonado@chromium.org

Change-Id: I0cf8a73a645865700dc8ce5c2d17cc1915706ca5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2131384
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>

man/html/depot_tools_tutorial.html

@@ -875,12 +875,12 @@ Litmus Test
 <div class="content">
 <pre><code><strong><span class="white">$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git</span></strong></code></pre>
 </div></div>
-<div class="paragraph"><p>Add <em>depot_tools</em> to the <em>end</em> of your PATH (you will probably want to put this
+<div class="paragraph"><p>Add <em>depot_tools</em> to the <em>front</em> of your PATH (you will probably want to put this
 in your <code>~/.bashrc</code> or <code>~/.zshrc</code>). Assuming you cloned <em>depot_tools</em> to
 <code>/path/to/depot_tools</code>:</p></div>
 <div class="listingblock">
 <div class="content">
-<pre><code><strong><span class="white">$ export PATH=$PATH:/path/to/depot_tools</span></strong></code></pre>
+<pre><code><strong><span class="white">$ export PATH=/path/to/depot_tools:$PATH</span></strong></code></pre>
 </div></div>
 </div>
 <div class="sect3">
@@ -898,7 +898,7 @@ extract the hidden &#8220;.git&#8221; folder which is necessary for <em>depot_to
 autoupdate itself. You can use &#8220;Extract all&#8230;&#8221; from the context menu though.</td>
 </tr></table>
 </div>
-<div class="paragraph"><p>Add <em>depot_tools</em> to the <em>start</em> of your PATH (must be ahead of any installs of
+<div class="paragraph"><p>Add <em>depot_tools</em> to the <em>front</em> of your PATH (must be ahead of any installs of
 Python). Assuming you unzipped the bundle to <code>C:\workspace\depot_tools</code>:</p></div>
 <div class="dlist"><dl>
 <dt class="hdlist1">

man/src/depot_tools_tutorial.txt

@@ -96,7 +96,7 @@ extract it somewhere.
 extract the hidden ``.git'' folder which is necessary for 'depot_tools' to
 autoupdate itself. You can use ``Extract all...'' from the context menu though.
 
-Add 'depot_tools' to the 'start' of your PATH (must be ahead of any installs of
+Add 'depot_tools' to the 'front' of your PATH (must be ahead of any installs of
 Python). Assuming you unzipped the bundle to `C:\workspace\depot_tools`:
 
 With Administrator access: ::