Add and apply property-no-deprecated stylelint rule

This rule was introduced in stylelint 16.23. Out of the deprecated
properties it detects, we were only using `word-wrap`.

According to the CSS Working Group [1]:

> For legacy reasons, UAs must treat word-wrap as a legacy name alias of
> the overflow-wrap property.

Since there's universal browser support for `overflow-wrap: break-word`
[2], we can safely replace `word-wrap` with `overflow-wrap`.

[1] https://drafts.csswg.org/css-text/#overflow-wrap-property
[2] https://caniuse.com/mdn-css_properties_overflow-wrap_break-word

.stylelintrc.yml

@@ -29,6 +29,7 @@ rules:
   max-nesting-depth: 4
   media-feature-name-no-vendor-prefix: true
   no-invalid-position-declaration: true
+  property-no-deprecated: true
   property-no-unknown: true
   property-no-vendor-prefix: true
   rule-empty-line-before: