Use JS multi-line string for Python code

so that the Python code looks nicer and is less error-prone to edit.

src/console.html

@@ -24,16 +24,17 @@
         );
 
         window.term = term;
-        pyodide.runPython(
-          'import io, code, sys\n' +
-          'from js import term, pyodide\n' +
-          'class Console(code.InteractiveConsole):\n' +
-          '    def runcode(self, code):\n' +
-          '        sys.stdout = io.StringIO()\n' +
-          '        sys.stderr = io.StringIO()\n' +
-          '        term.runPython("\\n".join(self.buffer))\n' +
-          '_c = Console(locals=globals())'
-        )
+        pyodide.runPython(`
+          import io, code, sys
+          from js import term, pyodide
+
+          class Console(code.InteractiveConsole):
+              def runcode(self, code):
+                  sys.stdout = io.StringIO()
+                  sys.stderr = io.StringIO()
+                  term.runPython("\\n".join(self.buffer))
+          _c = Console(locals=globals())
+        `)
 
         var c = pyodide.pyimport('_c')