Manual tweaks on all SVGs

* Gives a consistent header to all images
* Makes future changes easier to see
* Some images slightly smaller
* Some images use SVG2 features (`href`)
* Most images smaller or the same size
* A few images slightly larger

images/svg/reddit.svg

@@ -1 +1,6 @@
-<svg fill="#ff4500" stroke-linecap="round" stroke-linejoin="round" viewBox="0 0 512 512" xmlns="http://www.w3.org/2000/svg" aria-label="Reddit"><rect height="512" rx="15%" width="512"/><g fill="#fff"><ellipse cx="256" cy="307" rx="166" ry="117"/><ellipse cx="106" cy="256" rx="42" ry="42"/><ellipse cx="407" cy="256" rx="42" ry="42"/></g><path d="m256 196 23-101 73 15" fill="none" stroke="#fff" stroke-width="16"/><ellipse cx="375" cy="114" fill="#fff" rx="32" ry="31"/><ellipse cx="191" cy="287" rx="31" ry="31"/><ellipse cx="321" cy="287" rx="31" ry="31"/><path d="m191 359c33 25 97 26 130 0" fill="none" stroke="#ff4500" stroke-width="13"/></svg>
+<svg xmlns="http://www.w3.org/2000/svg"
+aria-label="Reddit" role="img"
+viewBox="0 0 512 512"><rect
+width="512" height="512"
+rx="15%"
+fill="#f40"/><g fill="#fff"><ellipse cx="256" cy="307" rx="166" ry="117"/><circle cx="106" cy="256" r="42"/><circle cx="407" cy="256" r="42"/><circle cx="375" cy="114" r="32"/></g><g stroke-linecap="round" stroke-linejoin="round" fill="none"><path d="m256 196 23-101 73 15" stroke="#fff" stroke-width="16"/><path d="m191 359c33 25 97 26 130 0" stroke="#f40" stroke-width="13"/></g><g fill="#f40"><circle cx="191" cy="287" r="31"/><circle cx="321" cy="287" r="31"/></g></svg>