Vale: Avoid annotating text in HTML a elements

The custom spelling rule that we maintain to avoid noise about words with camel-case, especially, API names. This leads to vale warnings with a elements, which are otherwise ignored. The following are the possible alternatives to fix this issue:

• Modify the regex used for the custom spelling rule
• Update the vocabularies list with tokens that are warned about the most, but they should be ignored by vale.
• Modify the script to check if a warning is within the context of an anchor attributes, and ignore such vale warnings.