Fix the color of documentation icon

frontend/src/assets/documentation.svg

@@ -1,3 +1,3 @@
 <svg xmlns="http://www.w3.org/2000/svg" x="0px" y="0px" width="100" height="100" viewBox="0,0,256,256">
-    <g transform="translate(-19.2,-19.2) scale(1.15,1.15)"><g fill="#605b5b" fill-rule="nonzero" stroke="none" stroke-width="1" stroke-linecap="butt" stroke-linejoin="miter" stroke-miterlimit="10" stroke-dasharray="" stroke-dashoffset="0" font-family="none" font-weight="none" font-size="none" text-anchor="none" style="mix-blend-mode: normal"><g transform="scale(10.66667,10.66667)"><path d="M13.172,2h-7.172c-1.1,0 -2,0.9 -2,2v16c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2v-11.172c0,-0.53 -0.211,-1.039 -0.586,-1.414l-4.828,-4.828c-0.375,-0.375 -0.884,-0.586 -1.414,-0.586zM15,18h-6c-0.552,0 -1,-0.448 -1,-1v0c0,-0.552 0.448,-1 1,-1h6c0.552,0 1,0.448 1,1v0c0,0.552 -0.448,1 -1,1zM15,14h-6c-0.552,0 -1,-0.448 -1,-1v0c0,-0.552 0.448,-1 1,-1h6c0.552,0 1,0.448 1,1v0c0,0.552 -0.448,1 -1,1zM13,9v-5.5l5.5,5.5z"></path></g></g></g>
-    </svg>
+    <g transform="translate(-19.2,-19.2) scale(1.15,1.15)"><g fill="black" fill-opacity="0.5" fill-rule="nonzero" stroke="none" stroke-width="1" stroke-linecap="butt" stroke-linejoin="miter" stroke-miterlimit="10" stroke-dasharray="" stroke-dashoffset="0" font-family="none" font-weight="none" font-size="none" text-anchor="none" style="mix-blend-mode: normal"><g transform="scale(10.66667,10.66667)"><path d="M13.172,2h-7.172c-1.1,0 -2,0.9 -2,2v16c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2v-11.172c0,-0.53 -0.211,-1.039 -0.586,-1.414l-4.828,-4.828c-0.375,-0.375 -0.884,-0.586 -1.414,-0.586zM15,18h-6c-0.552,0 -1,-0.448 -1,-1v0c0,-0.552 0.448,-1 1,-1h6c0.552,0 1,0.448 1,1v0c0,0.552 -0.448,1 -1,1zM15,14h-6c-0.552,0 -1,-0.448 -1,-1v0c0,-0.552 0.448,-1 1,-1h6c0.552,0 1,0.448 1,1v0c0,0.552 -0.448,1 -1,1zM13,9v-5.5l5.5,5.5z"></path></g></g></g>
+</svg>