Fix pills being broken by unescaped characters

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

src/editor/deserialize.js

@@ -50,7 +50,7 @@ function parseLink(a, partCreator) {
             if (href === a.textContent) {
                 return partCreator.plain(a.textContent);
             } else {
-                return partCreator.plain(`[${a.textContent}](${href})`);
+                return partCreator.plain(`[${a.textContent.replace(/[\\\]]/, c => "\\" + c)}](${href})`);
             }
         }
     }

src/editor/serialize.js

@@ -30,7 +30,7 @@ export function mdSerialize(model) {
                 return html + part.text;
             case "room-pill":
             case "user-pill":
-                return html + `[${part.text}](${makeGenericPermalink(part.resourceId)})`;
+                return html + `[${part.text.replace(/[\\\]]/, c => "\\" + c)}](${makeGenericPermalink(part.resourceId)})`;
         }
     }, "");
 }