Increase font size by a smidge

In trying to follow [APCA][1], we need bigger fonts in order to have
more colors in a dark mode.

[1]: https://github.com/Myndex/SAPC-APCA

Author: shepmaster

ui/frontend/Help.module.css

@@ -4,7 +4,7 @@
   background-color: var(--background-color-high-contrast);
   padding: 1em;
   max-width: 800px;
-  line-height: 1.5;
+  line-height: 1.25;
 }
 
 .code {

ui/frontend/Output.module.css

@@ -16,7 +16,7 @@
   border: var(--border);
   border-right: none;
   background-color: var(--output-background-tab);
-  line-height: 1.5em;
+  line-height: 1.5;
 
   &:last-of-type {
     border-right: var(--border);

ui/frontend/index.module.css

@@ -205,6 +205,7 @@ body {
   background-color: var(--background-color);
   padding: 0 1em;
   font-family: var(--primary-font);
+  font-size: 18px;
 }
 
 /* stylelint-disable-next-line selector-class-pattern */

ui/frontend/shared.module.css

@@ -1,5 +1,6 @@
 .-bodyMonospace {
-  font-size: 0.9em;
+  font-size: inherit;
+  line-height: 1.25;
 
   /* http://code.stephenmorley.org/html-and-css/fixing-browsers-broken-monospace-font-handling/
    * ACE uses Monaco, Menlo, "Ubuntu Mono", Consolas, source-code-pro, monospace;