Add more api demos (#1845)

* Added function Demos
* Added use-package demos
* Some corrections
* Fix duplicated use-package! type

docs/api.org

@@ -27,6 +27,7 @@ It is integrated into Helpful, in Doom.
     - [[#remove-hook][remove-hook!]]
     - [[#setq-hook][setq-hook!]]
     - [[#unsetq-hook][unsetq-hook!]]
+    - [[#use-package][use-package!]]
 - [[#interesting-snippets][Interesting snippets]]
   - [[#persist-emacs-initial-frame-size-across-sessions][Persist Emacs' initial frame size across sessions]]
   - [[#persist-emacs-initial-frame-position-dimensions-andor-full-screen-state-across-sessions][Persist Emacs' initial frame position, dimensions and/or full-screen state across sessions]]
@@ -159,7 +160,12 @@ It is integrated into Helpful, in Doom.
 
 *** TODO defer-feature!
 *** TODO defer-until!
-*** TODO disable-packages!
+*** disable-packages!
+#+BEGIN_SRC elisp :eval no
+;; Disable packages enabled by DOOM
+(disable-packages! some-package second-package)
+#+END_SRC
+
 *** doom!
 #+BEGIN_SRC elisp :eval no
 (doom! :completion
@@ -220,7 +226,31 @@ It is integrated into Helpful, in Doom.
 (load! "~/.maynotexist" nil t)
 #+END_SRC
 
-*** TODO map!
+*** map!
+#+BEGIN_SRC elisp :eval no
+(map! :map magit-mode-map
+      :m  "C-r" 'do-something           ; C-r in motion state
+      :nv "q" 'magit-mode-quit-window   ; q in normal+visual states
+      "C-x C-r" 'a-global-keybind
+      :g "C-x C-r" 'another-global-keybind  ; same as above
+
+      (:when IS-MAC
+        :n "M-s" 'some-fn
+        :i "M-o" (lambda (interactive) (message "Hi"))))
+
+(map! (:when (featurep! :completion company) ; Conditional loading
+        :i "C-@" #'+company/complete
+        (:prefix "C-x"                       ; Use a prefix key
+          :i "C-l" #'+company/whole-lines)))
+
+(map! (:when (featurep! :lang latex)    ; local conditional
+        (:map LaTeX-mode-map
+          :localleader                  ; Use local leader
+          :desc "View" "v" #'TeX-view)) ; Add which-key description
+      :leader                           ; Use leader key from now on
+      :desc "Eval expression" ";" #'eval-expression)
+#+END_SRC
+
 *** package!
 #+BEGIN_SRC elisp :eval no
 ;; To install a package that can be found on ELPA or any of the sources
@@ -257,7 +287,11 @@ It is integrated into Helpful, in Doom.
 #+END_SRC
 
 *** TODO pushnew!
-*** TODO quiet!
+*** quiet!
+#+BEGIN_SRC elisp :eval no
+;; Enters recentf-mode without extra output
+(quiet! (recentf-mode +1))
+#+END_SRC
 *** remove-hook!
 #+BEGIN_SRC elisp :eval no
 ;; With only one hook and one function, this is identical to `remove-hook'. In
@@ -276,9 +310,47 @@ It is integrated into Helpful, in Doom.
 ;; Removing arbitrary forms (must be exactly the same as the definition)
 (remove-hook! (one-mode second-mode) (setq v 5) (setq a 2))
 #+END_SRC
-*** TODO setq-hook!
-*** TODO unsetq-hook!
+*** setq-hook!
+#+BEGIN_SRC elisp :eval no
+;; Set multiple variables after a hook
+(setq-hook! 'markdown-mode-hook
+  line-spacing 2
+  fill-column 80)
 
+;; Set variables after multiple hooks
+(setq-hook! '(eshell-mode-hook term-mode-hook)
+  hscroll-margin 0)
+#+END_SRC
+
+*** unsetq-hook!
+#+BEGIN_SRC elisp :eval no
+(unsetq-hook! 'markdown-mode-hook line-spacing)
+
+;; Removes the following variable hook
+(setq-hook! 'markdown-mode-hook line-spacing 2)
+
+;; Removing N variables from M hooks
+(unsetq-hook! some-mode enable-something and-another)
+(unsetq-hook! some-mode (enable-something and-another))
+(unsetq-hook! '(one-mode-hook second-mode-hook) enable-something)
+(unsetq-hook! (one-mode second-mode) enable-something)
+#+END_SRC
+
+*** use-package!
+#+BEGIN_SRC elisp :eval no
+;; Use after-call to load package before hook
+(use-package! projectile
+  :after-call (pre-command-hook after-find-file dired-before-readin-hook))
+
+;; defer recentf packages one by one
+(use-package! recentf
+  :defer-incrementally easymenu tree-widget timer
+  :after-call after-find-file)
+
+;; This is equivalent to :defer-incrementally (abc)
+(use-package! abc
+  :defer-incrementally t)
+#+END_SRC
 * Interesting snippets
 ** Persist Emacs' initial frame size across sessions
 #+BEGIN_SRC elisp