Fix tide failure in magit buffers.

When a user uses magit to extract old commits of files, magit creates buffers
for these commits. These buffers are not backed by actual files. Tide is turned
on in these buffers. Prior to this commit tide would report errors whenever it
tried to contact `tsserver` to work on one of these buffers. This commit makes
it so that tide detects that it is running in a magit buffer and aborts.

Author: lddubeau

tide.el

@@ -2088,6 +2088,15 @@ current buffer."
                                    tide--minimal-emacs emacs-version)
                      :error))
 
+  ;; When a user uses magit to extract old commits of files, magit creates
+  ;; buffers for those commits. These buffers are not backed by actual
+  ;; files. However, magit "cheats" and sets `buffer-file-name' when it turns on
+  ;; the modes on the file. So when this code runs in such a buffer,
+  ;; `buffer-file-name' is set, even though the buffer is not backed by a file
+  ;; on disk. So we need this check to handle such cases.
+  (when (bound-and-true-p magit-buffer-file-name)
+    (error "Cannot run tide in a buffer created by magit"))
+
   ;; Indirect buffers embedded in other major modes such as those in org-mode or
   ;; template languages have to be manually synchronized to tsserver. This might
   ;; cause problems in files with lots of small blocks of TypeScript. In that
@@ -2096,6 +2105,7 @@ current buffer."
   (unless (stringp buffer-file-name)
     (setq tide-require-manual-setup t))
 
+
   (set (make-local-variable 'eldoc-documentation-function)
        'tide-eldoc-function)
   (set (make-local-variable 'imenu-auto-rescan) t)