Fix bindings for `org-next-block' and `org-preview-block'.

Thanks to François and Sébastien for reporting this.

lisp/org.el

@@ -18473,8 +18473,8 @@ BEG and END default to the buffer boundaries."
 (org-defkey org-mode-map "\C-c\C-_" 'org-down-element)
 (org-defkey org-mode-map "\C-c\C-f" 'org-forward-heading-same-level)
 (org-defkey org-mode-map "\C-c\C-b" 'org-backward-heading-same-level)
-(org-defkey org-mode-map "\C-c\C-F" 'org-next-block)
-(org-defkey org-mode-map "\C-c\C-B" 'org-previous-block)
+(org-defkey org-mode-map "\C-c\M-f" 'org-next-block)
+(org-defkey org-mode-map "\C-c\M-b" 'org-previous-block)
 (org-defkey org-mode-map "\C-c$"    'org-archive-subtree)
 (org-defkey org-mode-map "\C-c\C-x\C-s" 'org-advertized-archive-subtree)
 (org-defkey org-mode-map "\C-c\C-x\C-a" 'org-archive-subtree-default)
@@ -18604,8 +18604,8 @@ BEG and END default to the buffer boundaries."
     ("p" . (org-speed-move-safe 'outline-previous-visible-heading))
     ("f" . (org-speed-move-safe 'org-forward-heading-same-level))
     ("b" . (org-speed-move-safe 'org-backward-heading-same-level))
-    ("F" . (org-speed-move-safe 'org-next-block))
-    ("B" . (org-speed-move-safe 'org-previous-block))
+    ("F" . org-next-block)
+    ("B" . org-previous-block)
     ("u" . (org-speed-move-safe 'outline-up-heading))
     ("j" . org-goto)
     ("g" . (org-refile t))