Fix default Alt+W keybinding (#6110)

* Fix default Alt+W keybinding

The old keybinding would chop off the last line of the `whatis` output
when using a multi-line prompt. This fix corrects that.

* Make variable local and remove unneeded if statement

* Test that token is non-empty

share/functions/__fish_shared_key_bindings.fish

@@ -80,7 +80,7 @@ function __fish_shared_key_bindings -d "Bindings shared between emacs and vi mod
     bind --preset $argv \e. history-token-search-backward
 
     bind --preset $argv \el __fish_list_current_token
-    bind --preset $argv \ew 'set tok (commandline -pt); if test -n "$tok[1]"; echo; whatis $tok[1]; commandline -f repaint; end'
+    bind --preset $argv \ew __fish_whatis_current_token
     # ncurses > 6.0 sends a "delete scrollback" sequence along with clear.
     # This string replace removes it.
     bind --preset $argv \cl 'echo -n (clear | string replace \e\[3J ""); commandline -f repaint'

share/functions/__fish_whatis_current_token.fish

@@ -0,0 +1,17 @@
+# This function is typically bound to Alt-W, it is used to list man page entries
+# for the command under the cursor.
+function __fish_whatis_current_token -d "Show man page entries related to the token under the cursor"
+    set -l tok (commandline -pt)
+
+    if test -n "$tok[1]"
+        printf "\n"
+        whatis $tok[1]
+
+        set -l line_count (count (fish_prompt))
+        for x in (seq 2 $line_count)
+            printf "\n"
+        end
+
+        commandline -f repaint
+    end
+end