Small changes to 4 files for 8.6

[Jennifer Hodgdon]

I wanted to let you know that on this issue:
https://www.drupal.org/project/user_guide/issues/3001213
we made small changes to the following English source file(s), to make them consistent with small changes in the UI of Drupal between 8.5 and 8.6, as well as small changes on drupal.org:

content-create.txt and language-content-translate.txt: The "URL path settings" section of node editing forms now says "URL alias" instead

extend-module-find.txt: drupal.org search page for modules now says "Search modules" instead of "Search Modules" (capitalization change)

extend-theme-find.txt: same thing for "Search themes" in place of "Search Themes"

Screenshots for English and of the drupal.org pages have also been updated accordingly. Screenshots for 8.6 for other languages will be coming soon.

Here is the commit for reference:
https://cgit.drupalcode.org/user_guide/commit/?id=026c20c

Suggested actions to respond to this change in each language for each of these files would be either:
a) If the file hasn't been translated yet, copy the English source file to your language directory and commit it.
b) If the file has already been translated, open a new issue to revise the translation.