Client settings cannot be overridden

[vljosa-vivodyne]

Thank you for the bug report

• I am using the latest version of lsp-mode related packages.
• I checked FAQ and Troubleshooting sections
• You may also try reproduce the issue using clean environment using the following command: M-x lsp-start-plain

Bug description

Calling lsp-register-custom-settings twice does not properly override the value because the hash table is created with the default :test 'eql. Therefore, when I try to override a setting using a string that is equal to the one used previously, it's added to the hash table as a new key.

Steps to reproduce

(clrhash lsp-client-settings)
(lsp-register-custom-settings '(("foo" "original value")))
(lsp-register-custom-settings '(("foo" "new value")))

(let ((hash-table-contents nil))
  (maphash (lambda (k v) (push (cons k v) hash-table-contents))
	   lsp-client-settings)
  hash-table-contents)
;; => (("foo" "new value") ("foo" "original value"))

(gethash "foo" lsp-client-settings)
;; => nil

Expected behavior

(let ((hash-table-contents nil))
  (maphash (lambda (k v) (push (cons k v) hash-table-contents))
	   lsp-client-settings)
  hash-table-contents)
;; => (("foo" "new value"))

(gethash "foo" lsp-client-settings)
;; => ("new value")

Which Language Server did you use?

pyright-langserver (but it shouldn't matter)

OS

MacOS

Error callstack

No response

Anything else?

I'll submit a PR in a minute.