VS Code italics any theme / Night Owl italics

settings.json

{
  // [...] other settings
  // Copy this whole thing in your settings.json file ↓↓↓
  "editor.tokenColorCustomizations": {
    // NOTE: The asterisk targets all themes. If you want to target only specific ones
    // you can use the following notation instead (example with three themes + wildcard):
    // "[Atom One Dark][Default Dark+][*Monokai*]": {
    "[*]": {
      "textMateRules": [
        {
          "scope": [
            "markup.changed",
            "meta.diff.header.git",
            "meta.diff.header.from-file",
            "meta.diff.header.to-file",
            "markup.deleted.diff",
            "markup.inserted.diff",
            "comment",
            "punctuation.accessor",
            "keyword",
            "storage",
            "meta.var.expr",
            "meta.class meta.method.declaration meta.var.expr storage.type.js",
            "storage.type.property.js",
            "storage.type.property.ts",
            "storage.type.property.tsx",
            "entity.name.function",
            "entity.other.attribute-name",
            "keyword.operator.relational",
            "meta.delimiter.period",
            "meta.selector",
            "entity.name.tag.doctype",
            "meta.tag.sgml.doctype",
            "variable.other.object.property",
            "entity.name.function",
            "keyword.operator.comparison",
            "keyword.control.flow.js",
            "keyword.control.flow.ts",
            "keyword.control.flow.tsx",
            "keyword.control.ruby",
            "keyword.control.module.ruby",
            "keyword.control.class.ruby",
            "keyword.control.def.ruby",
            "keyword.control.loop.js",
            "keyword.control.loop.ts",
            "keyword.control.import.js",
            "keyword.control.import.ts",
            "keyword.control.import.tsx",
            "keyword.control.from.js",
            "keyword.control.from.ts",
            "keyword.control.from.tsx",
            "keyword.operator.instanceof.js",
            "keyword.operator.expression.instanceof.ts",
            "keyword.operator.expression.instanceof.tsx",
            "italic",
            "quote",
            "source.elixir .punctuation.binary.elixir",
            "source.go keyword.package.go",
            "source.go keyword.import.go",
            "source.go keyword.function.go",
            "source.go keyword.type.go",
            "source.go keyword.struct.go",
            "source.go keyword.interface.go",
            "source.go keyword.const.go",
            "source.go keyword.var.go",
            "source.go keyword.map.go",
            "source.go keyword.channel.go",
            "source.go keyword.control.go",
            "meta.tag.sgml.doctype.html",
            "variable.other.object.js",
            "markup.italic.markdown",
            "markup.quote.markdown",
            "keyword.control"
          ],
          "settings": {
            "fontStyle": "italic"
          }
        },
        {
          "scope": [
            "constant.numeric",
            "constant.character.numeric",
            "storage.type.function.arrow.js",
            "entity.name.tag",
            "meta.tag.other.html",
            "meta.tag.other.js",
            "meta.tag.other.tsx",
            "entity.name.tag.tsx",
            "entity.name.tag.js",
            "entity.name.tag",
            "meta.tag.js",
            "meta.tag.tsx",
            "meta.tag.html",
            "keyword.operator",
            "variable.parameter.function",
            "support.type.vendor.property-name",
            "support.constant.vendor.property-value",
            "support.type.property-name",
            "meta.property-list entity.name.tag",
            "keyword.operator.logical",
            "variable.other.object.js",
            "keyword.control.conditional.js",
            "keyword.control.conditional.ts",
            "keyword.control.switch.js",
            "keyword.control.switch.ts",
            "entity.name.tag.css",
            "entity.name.tag.less",
            "entity.name.tag.custom.css",
            "support.constant.property-value.css",
            "entity.name.type.js",
            "entity.name.type.module.js",
            "support.class.component.js",
            "support.class.component.tsx",
            "meta.property-list.css meta.property-value.css variable.other.less",
            "meta.property-list.scss variable.scss",
            "meta.property-list.sass variable.sass",
            "meta.brace",
            "keyword.operator.operator",
            "keyword.operator.or.regexp",
            "keyword.operator.expression.in",
            "keyword.operator.relational",
            "keyword.operator.assignment",
            "keyword.operator.comparison",
            "keyword.operator.type",
            "keyword.operator",
            "keyword",
            "punctuation.definintion.string",
            "punctuation",
            "variable.other.readwrite.js",
            "storage.type",
            "source.css",
            "string.quoted"
          ],
          "settings": {
            "fontStyle": ""
          }
        }
      ]
    }
  }
  // [...] more settings
}

Italics have been taken from https://github.com/sdras/night-owl-vscode-theme/