docs: remove some noisy spacing in pre-blocks

These newlines caused the blocks to have trailing newlines in them,
which renders a bit noisily.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>

docs/repository.html

@@ -51,17 +51,11 @@ To get the Mesa sources anonymously (read-only):
 <ol>
 <li>Install the git software on your computer if needed.
 <li>Get an initial, local copy of the repository with:
-    <pre>
-    git clone https://gitlab.freedesktop.org/mesa/mesa.git
-    </pre>
+    <pre>git clone https://gitlab.freedesktop.org/mesa/mesa.git</pre>
 <li>Later, you can update your tree from the master repository with:
-    <pre>
-    git pull origin
-    </pre>
+    <pre>git pull origin</pre>
 <li>If you also want the Mesa demos/tests repository:
-    <pre>
-    git clone https://gitlab.freedesktop.org/mesa/demos.git
-    </pre>
+    <pre>git clone https://gitlab.freedesktop.org/mesa/demos.git</pre>
 </ol>