Update and refine some icons (#35938)

Follow up to https://github.com/zed-industries/zed/pull/35856.

Release Notes:

- N/A

assets/icons/arrow_circle.svg

@@ -1,6 +1,6 @@
 <svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
-<path d="M3 5.77778L4.25556 4.52222C5.26054 3.55068 6.6022 3.00526 8 3C9.32608 3 10.5979 3.52678 11.5355 4.46447C12.2339 5.16285 12.7044 6.04656 12.899 7" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
-<path d="M3 3V5.77778H5.77778" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
-<path d="M13.0001 10.2222L11.7445 11.4778C10.7395 12.4493 9.39788 12.9947 8.00008 13C6.67399 13 5.40222 12.4732 4.46454 11.5355C3.76616 10.8372 3.29571 9.95344 3.10107 9" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
-<path d="M10.2224 10.2222H13.0002V13" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M12.8989 5.77778L11.6434 4.52222C10.6384 3.55068 9.29673 3.00526 7.89893 3C6.57285 3 5.30103 3.52678 4.36343 4.46447C3.78887 5.03901 3.36856 5.73897 3.12921 6.5" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M12.8989 3V5.77778H10.1211" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M3.1012 10.2222L4.3568 11.4778C5.3618 12.4493 6.70342 12.9947 8.10122 13C9.42731 13 10.6991 12.4732 11.6368 11.5355C12.2163 10.956 12.6389 10.2487 12.8772 9.47994" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M5.87891 10.2222H3.10111V13" stroke="black" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
 </svg>