Prefer buffer's major mode for rendering strings. (#4322)

Currently, when multiple major modes exist and are available for a
language (e.g., c-mode and c-ts-mode), the major mode used to render
strings is determined by the ordering of these modes within
`lsp-language-id-configuration'.  This ordering doesn't necessarily
reflect the preference of the user.

This change alters this behavior by preferring to render strings,
whose language matches that of the current buffer, with the same major
mode as the buffer.  When the string's language is different from the
buffer, the behavior falls back to selecting the first major mode
matching the language from `lsp-language-id-configuration'.

Author: brownts

lsp-mode.el

@@ -5516,10 +5516,11 @@ In addition, each can have property:
   "Render STR using `major-mode' corresponding to LANGUAGE.
 When language is nil render as markup if `markdown-mode' is loaded."
   (setq str (s-replace "\r" "" (or str "")))
-  (if-let ((mode (-some (-lambda ((mode . lang))
-                          (when (and (equal lang language) (functionp mode))
-                            mode))
-                        lsp-language-id-configuration)))
+  (if-let* ((modes (-keep (-lambda ((mode . lang))
+                            (when (and (equal lang language) (functionp mode))
+                              mode))
+                          lsp-language-id-configuration))
+            (mode (car (or (member major-mode modes) modes))))
       (lsp--fontlock-with-mode str mode)
     str))