mention am.framebuffer arg default values in docs

doc/index.html

@@ -2722,7 +2722,7 @@ <h1 id="framebuffers">Framebuffers</h1>
 <h2 id="creating-a-framebuffer">Creating a framebuffer</h2>
 <h3 id="am.framebuffer" class="func-def">am.framebuffer(texture [, depth_buf [, stencil_buf]])</h3>
 <p>Creates framebuffer with the given texture attached.</p>
-<p><code>depth_buf</code> and <code>stencil_buf</code> determine whether the framebuffer has a depth and/or stencil buffer. These should be <code>true</code> or <code>false</code>.</p>
+<p><code>depth_buf</code> and <code>stencil_buf</code> determine whether the framebuffer has a depth and/or stencil buffer. These should be <code>true</code> or <code>false</code> (default is <code>false</code>).</p>
 <h2 id="framebuffer-fields">Framebuffer fields</h2>
 <h3 id="framebuffer.clear_color" class="field-def">framebuffer.clear_color</h3>
 <p>The color to use when clearing the framebuffer (a <code>vec4</code>).</p>

doc/textures.md

@@ -195,7 +195,7 @@ Creates framebuffer with the given texture attached.
 
 `depth_buf` and `stencil_buf` determine whether the
 framebuffer has a depth and/or stencil buffer. These should be
-`true` or `false`.
+`true` or `false` (default is `false`).
 
 ## Framebuffer fields