Remove redundant section from .vale.ini

The .vale.ini file for linting tests contained a section for
instructions on how to lint just *.md files, and another section for
linting both *.md and *.txt files. If you included conflicting
instructions in those sections, Vale became very confused and did
not apply tests in the manner you might expect.

This commit removes the redundant section so test results will be
predictable and less error-prone.

.vale.ini

@@ -38,12 +38,3 @@ BasedOnStyles = gitlab
 # To change the reporting level (suggestion, warning, error) of a rule,
 # use the following format: {style}.{filename} = {level}
 # vale.Hedging = error
-
-# Syntax-specific settings
-# ------------------------
-# You can configure specific tests to be enabled, disabled, or report at a 
-# different level for specific file types. File-type-specific settings added
-# here will overwrite any conflicting global settings.
-[*.{md,txt}]
-# vale.Editorializing = NO
-