doc: improve SIGINT error text

* add kbd elements
* correct period/parenthesis order
* make fragment a full sentence

PR-URL: #35558
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

Author: Trott

Diff for: doc/api/errors.md

@@ -1714,8 +1714,8 @@ An attempt was made to `require()` an [ES Module][].
 <a id="ERR_SCRIPT_EXECUTION_INTERRUPTED"></a>
 ### `ERR_SCRIPT_EXECUTION_INTERRUPTED`
 
-Script execution was interrupted by `SIGINT` (For example, when Ctrl+C was
-pressed).
+Script execution was interrupted by `SIGINT` (For example,
+<kbd>Ctrl</kbd>+<kbd>C</kbd> was pressed.)
 
 <a id="ERR_SCRIPT_EXECUTION_TIMEOUT"></a>
 ### `ERR_SCRIPT_EXECUTION_TIMEOUT`