httpd: add a few more MIME types that we might want

Some more MIME file types that it seems more than plausible we might
want at some point in the future. Change the default type to
text/plain.

esp32/max80/httpd.c

@@ -59,12 +59,19 @@ struct mime_type {
 };
 
 static const struct mime_type mime_types[] = {
-    { ".html", 5, "text/html"                },
-    { ".css",  4, "text/css"                  },
-    { ".txt",  4, "text/plain; charset=UTF-8" },
-    { ".bin",  4, "application/octet-stream"  },
-    { ".fw",   3, "application/octet-stream"  },
-    { NULL,    0, "text/html"  } /* Default */
+    { ".html",  5, "text/html"                 },
+    { ".xhtml", 6, "text/html"                 },
+    { ".css",   4, "text/css"                  },
+    { ".webp",  5, "image/webp"                },
+    { ".jpg",   4, "image/jpeg"                },
+    { ".png",   4, "image/png"                 },
+    { ".ico",   4, "image/png"                 }, /* favicon.ico */
+    { ".svg",   4, "image/svg+xml"             },
+    { ".pdf",   4, "application/pdf"           },
+    { ".xml",   4, "text/xml"                  },
+    { ".bin",   4, "application/octet-stream"  },
+    { ".fw",    3, "application/octet-stream"  },
+    { NULL,     0, "text/plain; charset=UTF-8" }  /* default */
 };
 
 static esp_err_t httpd_static_handler(httpd_req_t *req)