Introduce key binding `sC` for `helm-swoop-clear-cache`

helm-swoop cannot detect the buffer has changed when calling git checkout to
change the file content, so helm-swoop won't clear the cache, we have to clear
the cache manually by evaluating `helm-swoop--clear-cache`. As it is
inconvenient, so I introduce a new key binding to to this.

Signed-off-by: Yang Qian <yang.qian@citrix.com>

CHANGELOG.develop

@@ -1472,6 +1472,7 @@ Other:
   removed upstream.
 - Load helm before read-file-name and completing-read
   (thanks duianto and thanks Miciah for a more elegant solution)
+- Added key binding `sC` for `helm-swoop-clear-cache` (thanks to Yang Qian)
 **** HTML
 - Added impatient-mode under ~SPC m i~ (thanks to geo7)
 - Added =counsel-css= as an =ivy= alternative to =helm-css-scss=

layers/+completion/helm/packages.el

@@ -370,8 +370,15 @@
                      (if thing thing ""))))))
           (call-interactively 'helm-swoop)))
 
+      (defun spacemacs/helm-swoop-clear-cache ()
+        "Call `helm-swoop--clear-cache' to clear the cache"
+        (interactive)
+        (helm-swoop--clear-cache)
+        (message "helm-swoop cache cleaned."))
+
       (spacemacs/set-leader-keys
         "ss"    'helm-swoop
+        "sC"    'spacemacs/helm-swoop-clear-cache
         "sS"    'spacemacs/helm-swoop-region-or-symbol
         "s C-s" 'helm-multi-swoop-all)
       (defadvice helm-swoop (before add-evil-jump activate)