Improve Tooltip font/layout consistency

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

res/css/views/elements/_Tooltip.scss

@@ -52,7 +52,7 @@ limitations under the License.
     display: none;
     position: fixed;
     border: 1px solid $menu-border-color;
-    border-radius: 4px;
+    border-radius: 8px;
     box-shadow: 4px 4px 12px 0 $menu-box-shadow-color;
     background-color: $menu-bg-color;
     z-index: 6000; // Higher than context menu so tooltips can be used everywhere
@@ -60,7 +60,7 @@ limitations under the License.
     pointer-events: none;
     line-height: $font-14px;
     font-size: $font-12px;
-    font-weight: 600;
+    font-weight: 500;
     color: $primary-fg-color;
     max-width: 200px;
     word-break: break-word;
@@ -87,3 +87,12 @@ limitations under the License.
         }
     }
 }
+
+.mx_Tooltip_title {
+    font-weight: 600;
+}
+
+.mx_Tooltip_sub {
+    opacity: 0.7;
+    margin-top: 4px;
+}