docs: rewrite paragraph to be free-form

These half-way structured sections are needlessly problematic to
translate cleanly to other markup-languages, so let's just make this
into a free-form paragraph instead.

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>
diff --git a/docs/install.html b/docs/install.html
index f4b3edd..df5fcd3 100644
--- a/docs/install.html
+++ b/docs/install.html
@@ -212,9 +212,8 @@
 </pre>
 
 <p>
-<b>libGL</b> is the main OpenGL library (i.e. Mesa).
-<br>
-<b>libOSMesa</b> is the OSMesa (Off-Screen) interface library.
+<b>libGL</b> is the main OpenGL library (i.e. Mesa), while <b>libOSMesa</b>
+is the OSMesa (Off-Screen) interface library.
 </p>
 
 <p>