Add t to the triple to indicate it is a boolean

As specified in `lsp-mode.el`:
 > (defun lsp-register-custom-settings (props)
 >   "Register PROPS.
 > PROPS is list of triple (path value boolean?) where PATH is the path to the
 > property; VALUE can be a literal value, symbol to be evaluated, or either a
 > function or lambda function to be called without arguments; BOOLEAN? is an
 > optional flag that should be non-nil for boolean settings, when it is nil the
 > property will be ignored if the VALUE is nil."

Author: abougouffa

lsp-ltex.el

@@ -489,7 +489,7 @@ This file is use to activate the language server."
    ("ltex.latex.commands" lsp-ltex-latex-commands)
    ("ltex.latex.environments" lsp-ltex-latex-environments)
    ("ltex.markdown.nodes" lsp-ltex-markdown-nodes)
-   ("ltex.additionalRules.enablePickyRules" lsp-ltex-additional-rules-enable-picky-rules)
+   ("ltex.additionalRules.enablePickyRules" lsp-ltex-additional-rules-enable-picky-rules t)
    ("ltex.additionalRules.motherTongue" lsp-ltex-mother-tongue)
    ("ltex.additionalRules.languageModel" lsp-ltex-additional-rules-language-model)
    ("ltex.additionalRules.neuralNetworkModel" lsp-ltex-additional-rules-neural-network-model)