Mark `public/img/svg/*.svg` as generated files (#24193)

These files are generated using `make svg`

.gitattributes

@@ -1,6 +1,7 @@
 * text=auto eol=lf
 *.tmpl linguist-language=Handlebars
 /assets/*.json linguist-generated
+/public/img/svg/*.svg linguist-generated
 /public/vendor/** -text -eol linguist-vendored
 /vendor/** -text -eol linguist-vendored
 /web_src/fomantic/build/** linguist-generated