Remove check that headings are sentence-case

The check doesn’t work in many case and causes a lot of noise in the build log.
For now, we can check this convention ourselves in reviews.

.vale.ini

@@ -10,24 +10,25 @@ vale.Redundancy = YES
 vale.Repetition = YES
 vale.Uncomparables = YES
 CockroachDB.Hyperbolic = NO
+CockroachDB.HeadingsCase = NO
 
 # Custom block scoping (see the regex101 links for unit tests):
-# 
+#
 # Rule #1 (https://regex101.com/r/TJQLJ4/2/tests): Ignore `{%comment%}` blocks. This
 # keeps Vale from flagging 'endcomment' as a spelling mistake.
 #
-# Rule #2 (https://regex101.com/r/7VA2lV/2/tests): Ignore `<div>`s and `<section>`s 
-# that specify `markdown="1"` since it isn't supported by Vale's Markdown 
+# Rule #2 (https://regex101.com/r/7VA2lV/2/tests): Ignore `<div>`s and `<section>`s
+# that specify `markdown="1"` since it isn't supported by Vale's Markdown
 # parser (https://github.com/russross/blackfriday/issues/184).
-# 
+#
 # Rule #3 (https://regex101.com/r/NxFflU/1/tests): Ignore `{% include %}`-codeblock
 # pairs.
 BlockIgnores = (?s)({%\s?comment\s?%}.+?{%\s?endcomment\s?%}), \
 (?s)(<(?:div|section)[^>]*markdown="1"[^>]*>.*?</(?:div|section)>), \
 (?s)((?: *{% include [^%]+ %}\n)? *~~~.*?~~~~?)
 
 # Custom inline scoping (see the regex101 links for unit tests):
-# 
+#
 # Rule #1 (https://regex101.com/r/cTiITH/2/tests): Ignore `{% include %}`s, which
 # contain file paths.
-TokenIgnores = ({%\s?include\s? {{ [^}]+ }}[^%]+\s?%})
+TokenIgnores = ({%\s?include\s? {{ [^}]+ }}[^%]+\s?%})