Option to keep spaces before inline comments

Add a keepSpaces or keepSpacesBeforeLineComments similar too keepLines that preserves the spaces between values and inline comments at the end of the line.

This will help to avoid unnecessary changes when formatting tsconfig.json files:

Original:

    /* Language and Environment */
    "target": "es2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */

Formatted:

    /* Language and Environment */
    "target": "es2016", /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */

Diff:

     /* Language and Environment */
-    "target": "es2016",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    "target": "es2016", /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
     // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */

Empieza leyendo la opción keepLines existente y el pull request enlazado; después, sigue la API del formateador que gestiona los comentarios en línea. Usa los ejemplos de tsconfig.json como referencia del comportamiento: cuando la nueva opción esté habilitada, se deben conservar los espacios antes de los comentarios al final de línea sin cambiar ningún otro formato.