feat(evil): vim completion keybinds on C-x

Vim has a set of completion commands bound to the C-x prefix. We had
this for company, but with this commit, we now have them for the corfu
module.

modules/completion/corfu/autoload.el

@@ -37,3 +37,13 @@
          (save-excursion (backward-char 1)
                          (insert-char ?\\)))
         (t (call-interactively #'corfu-insert-separator))))
+
+;;;###autoload
+(defun +corfu/dabbrev-this-buffer ()
+  "Like `cape-dabbrev', but only scans current buffer."
+  (interactive)
+  (require 'cape)
+  (let ((cape-dabbrev-check-other-buffers nil))
+    (cape-dabbrev t)))
+
+;;; end of autoload.el

modules/editor/evil/config.el

@@ -576,15 +576,25 @@ directives. By default, this only recognizes C directives.")
       :v "gl" #'evil-lion-left
       :v "gL" #'evil-lion-right
 
-      ;; Omni-completion
-      (:when (modulep! :completion company)
-       (:prefix "C-x"
-        :i "C-l"    #'+company/whole-lines
-        :i "C-k"    #'+company/dict-or-keywords
-        :i "C-f"    #'company-files
-        :i "C-]"    #'company-etags
-        :i "s"      #'company-ispell
-        :i "C-s"    #'company-yasnippet
-        :i "C-o"    #'company-capf
-        :i "C-n"    #'+company/dabbrev
-        :i "C-p"    #'+company/dabbrev-code-previous)))
+      ;; Emulation of Vim's omni-completion keybinds
+      (:prefix "C-x"
+        (:when (modulep! :completion company)
+         :i "C-l"  #'+company/whole-lines
+         :i "C-k"  #'+company/dict-or-keywords
+         :i "C-f"  #'company-files
+         :i "C-]"  #'company-etags
+         :i "s"    #'company-ispell
+         :i "C-s"  #'company-yasnippet
+         :i "C-o"  #'company-capf
+         :i "C-n"  #'+company/dabbrev
+         :i "C-p"  #'+company/dabbrev-code-previous)
+        (:when (modulep! :completion corfu)
+         :i "C-l"  #'cape-line
+         :i "C-k"  #'cape-keyword
+         :i "C-f"  #'cape-file
+         :i "C-]"  #'complete-tag
+         :i "s"    #'cape-dict
+         :i "C-s"  #'yasnippet-capf
+         :i "C-o"  #'completion-at-point
+         :i "C-n"  #'cape-dabbrev
+         :i "C-p"  #'+corfu/dabbrev-this-buffer)))