[UK] Fix validation errors

I found errors in 3 files and fixed them with the commit above. I'll see about deployment to drupal.org.

Meanwhile, there is also a warning reported in PDF generation about some characters that are not available in the Courier font:
(page 2-3)
[WARN] FOUserAgent - Glyph "м" (0x43c, afii10078) not available in font "Courier".
[WARN] FOUserAgent - Glyph "о" (0x43e, afii10080) not available in font "Courier".
[WARN] FOUserAgent - Glyph "н" (0x43d, afii10079) not available in font "Courier".
[WARN] FOUserAgent - Glyph "ш" (0x448, afii10090) not available in font "Courier".
[WARN] FOUserAgent - Glyph "і" (0x456, afii10103) not available in font "Courier".
[WARN] FOUserAgent - Glyph "р" (0x440, afii10082) not available in font "Courier".
[WARN] FOUserAgent - Glyph "и" (0x438, afii10074) not available in font "Courier".
(page 159-160)
[WARN] FOUserAgent - Glyph "С" (0x421, Escyrillic) not available in font "Courier".

I am not really sure where those are coming from. I don't see anything in Courier fonts on those pages... usually that would be command-line commands that we would put in a monospace font, but I don't see anything like that on those pages. Anyway, you might want to look at the attached PDF and see if you see anything wrong.

One more validation error: All "summary" lines need to be less than 140 characters. One isn't -- looks like it is the Chapter 2 summary. I"ll let you fix that one. In the guide.asciidoc file.

[[planning-chapter]]
== Планування сайту

[role="summary"]
Огляд концепцій планування сайтів та подробиць основних способів використання макета сайту. Розглянуті поняття сутності матеріалів та структури.

Looks like that should do it -- thanks for the quick action!