Forbid deprecated break-word in CSS (#30934)

Forbid
[deprecated](https://drafts.csswg.org/css-text-3/#word-break-property)
`break-word` and fix all occurences.

Regarding `overflow-wrap: break-word` vs `overflow-wrap: anywhere`:

Example of difference: https://jsfiddle.net/silverwind/1va6972r/

[Here](https://stackoverflow.com/questions/77651244) it says:

> The differences between normal, break-word and anywhere are only clear
if you are using width: min-content on the element containing the text,
and you also set a max-width. A pretty rare scenario.

I don't think this difference will make any practical impact as we are
not hitting this rare scenario.

web_src/css/repo.css

@@ -410,7 +410,7 @@ td .commit-summary {
 }
 
 .repository.file.list .non-diff-file-content .plain-text pre {
-  word-break: break-word;
+  overflow-wrap: anywhere;
   white-space: pre-wrap;
 }