Consistently reference theme_root_icon (#163)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>
Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: 4 people

python_docs_theme/layout.html

@@ -14,7 +14,7 @@ <h3>{{ _('Navigation') }}</h3>
           </li>
           {%- endfor %}
           {%- block rootrellink %}
-          <li><img src="{{ pathto('_static/py.svg', 1) }}" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
+          <li><img src="{{ pathto('_static/' ~ theme_root_icon, 1) }}" alt="{{ theme_root_icon_alt_text }}" style="vertical-align: middle; margin-top: -1px"/></li>
           <li><a href="{{theme_root_url}}">{{theme_root_name}}</a>{{ reldelim1 }}</li>
           <li class="switchers">
             <div class="language_switcher_placeholder"></div>
@@ -71,7 +71,7 @@ <h3>{{ _('Navigation') }}</h3>
 
 {%- block extrahead -%}
     <link rel="stylesheet" href="{{ pathto('_static/pydoctheme_dark.css', 1) }}" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
-    <link rel="shortcut icon" type="image/png" href="{{ pathto('_static/' + theme_root_icon, 1) }}" />
+    <link rel="shortcut icon" type="image/png" href="{{ pathto('_static/' ~ theme_root_icon, 1) }}" />
     {%- if builder != "htmlhelp" %}
         {%- if not embedded %}
             <script type="text/javascript" src="{{ pathto('_static/copybutton.js', 1) }}"></script>
@@ -100,7 +100,7 @@ <h3>{{ _('Navigation') }}</h3>
         </label>
         <span class="nav-items-wrapper">
             <a href="{{ theme_root_url }}" class="nav-logo">
-                <img src="{{ pathto('_static/py.svg', 1) }}" alt="Logo"/>
+                <img src="{{ pathto('_static/' ~ theme_root_icon, 1) }}" alt="{{ theme_root_icon_alt_text }}"/>
             </a>
             <span class="version_switcher_placeholder"></span>
             {%- if pagename != "search" and builder != "singlehtml" %}
@@ -121,7 +121,7 @@ <h3>{{ _('Navigation') }}</h3>
             {%- if logo %}
             <p class="logo">
                 <a href="{{ pathto('index') }}">
-                <img class="logo" src="{{ pathto('_static/' + logo, 1)|e }}" alt="Logo"/>
+                <img class="logo" src="{{ pathto('_static/' ~ logo, 1)|e }}" alt="Logo"/>
                 </a>
             </p>
             {%- endif %}

python_docs_theme/theme.conf

@@ -31,5 +31,6 @@ license_url =
 root_name = Python
 root_url = https://www.python.org/
 root_icon = py.svg
+root_icon_alt_text = Python logo
 root_include_title = True
 copyright_url =