[Emacs] Renamed Spacemacs configuration page to Emacs

Referring to the previous commit, it is actually better if the mu4e
headers view sets its own width _when a message is opened_ and not
when the headers view itself is opened. This commit also makes it so
that the width is evaluated based on the width of the window of the
headers view’s window rather than the width of the frame since the
message will be opened in a new window that will spawn in the headers
view's window.

org/config/sitemap.org

@@ -2,6 +2,7 @@
 
 - [[file:awesome.org][AwesomeWM configuration]]
 - [[file:bin.org][Executable scripts]]
+- [[file:spacemacs.org][Emacs Configuration]]
 - [[file:fish.org][Fish config]]
 - [[file:nano.org][Nano configuration (Deprecated)]]
 - [[file:ncmpcpp.org][Ncmpcpp Configuration (WIP)]]
@@ -11,6 +12,5 @@
 - [[file:picom.org][Picom (Compton) Configuration]]
 - [[file:polybar.org][Polybar config (Deprecated)]]
 - [[file:rustfmt.org][Rust format config]]
-- [[file:spacemacs.org][Spacemacs Configuration]]
 - [[file:tmux.org][Tmux config]]
-- [[file:i3.org][i3 config (Deprecated)]]
+- [[file:i3.org][i3 config (Deprecated)]]

org/config/spacemacs.org

@@ -1,4 +1,4 @@
-#+title: Spacemacs Configuration
+#+title: Emacs Configuration
 #+setupfile: headers
 #+OPTIONS: auto-id:t
 #+HTML_HEAD_EXTRA: <meta name="description" content="Phundrak’s Spacemacs Configuration" />
@@ -3227,12 +3227,13 @@
    horizontal. And to make it more  readable, the header window will only occupy
    40% of Emacs’  frame, the rest will be  given to emails. As you  can see, the
    width of the mu4e headers is evaluated each time we enter it, so it can react
-   to the frame being potentially not the same width than earlier.
+   to the frame being potentially not the  same width than earlier or the window
+   not taking the entire frame.
    #+BEGIN_SRC emacs-lisp
      (setq mu4e-split-view 'vertical)
-     (add-hook 'mu4e-headers-mode-hook
+     (add-hook 'mu4e-view-mode-hook
                (lambda ()
-                 (setq mu4e-headers-visible-columns (round (* (frame-total-cols)
+                 (setq mu4e-headers-visible-columns (round (* (window-width)
                                                               0.4)))))
    #+END_SRC