test: spellcheck :help (vimdoc) files #24109

Enforce consistent terminology (defined in
`gen_help_html.lua:spell_dict`) for common misspellings.

This does not spellcheck English in general (perhaps a future TODO,
though it may be noisy).

runtime/lua/vim/lsp/buf.lua

@@ -159,7 +159,7 @@ end
 --- @param options table|nil Optional table which holds the following optional fields:
 ---     - formatting_options (table|nil):
 ---         Can be used to specify FormattingOptions. Some unspecified options will be
----         automatically derived from the current Neovim options.
+---         automatically derived from the current Nvim options.
 ---         See https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#formattingOptions
 ---     - timeout_ms (integer|nil, default 1000):
 ---         Time in milliseconds to block for formatting requests. No effect if async=true