Add Alt as modifier key to git log search key binding (#17)

After much feedback around git log search's Ctrl+l key binding conflicting with clear screen, I have decided to change its key binding to Ctrl+Alt+l. An alternative option I considered was just Alt+l, which is shorter but I realized conflicts with __fish_list_current_token, which is actually quite useful and I plan on using it now that I've discovered it.

One huge problem with this change is that it is backwards incompatible and fisher has not provided me with a way to announce to users of fzf.fish that the key binding has changed. I had considered using a hack of checking if an arbitrary file existed, printing an error message if it doesn't and then creating that file, but it adds a lot of difficult-to-maintain code and slows down the shell startup.
Hopefully, people who discover that Ctrl+l no longer works will come to this repo and see this commit. I will also create a new release announcing this change. I am sorry for any confusion caused by this.

README.md

@@ -8,7 +8,7 @@ A plugin that integrates [fzf](https://github.com/junegunn/fzf) into your [fish]
 
 ![file search](/images/file_search.png)
 
-> Search for a **commit** in the current git repository's log - `Ctrl+l` (l for log)
+> Search for a **commit** in the current git repository's log - `Ctrl+Alt+l` (l for log, Alt to prevent overriding clear screen)
 
 ![git log search](/images/git_log_search.png)
 

conf.d/fzf.fish

@@ -1,17 +1,19 @@
 # Set up the default, mnemonic keybindings unless the user has chosen to customize them
 if not set --query fzf_fish_custom_keybindings
-    # \cf is ctrl+f, etc.
+    # \cf is Ctrl+f
     bind \cf '__fzf_search_current_dir'
-    bind \cl '__fzf_search_git_log'
     bind \cr '__fzf_search_history'
     bind \cv '__fzf_search_shell_variables'
+    # __fzf_search_git_log's keybinding has Alt as an additional modifier key to avoid conflict with
+    # clear screen (Ctrl+l) and __fish_list_current_token (Alt+l)
+    bind \e\cl '__fzf_search_git_log'
 
     # set up the same keybindings for insert mode if using fish_vi_key_bindings
     if [ $fish_key_bindings = 'fish_vi_key_bindings' ]
         bind --mode insert \cf '__fzf_search_current_dir'
-        bind --mode insert \cl '__fzf_search_git_log'
         bind --mode insert \cr '__fzf_search_history'
         bind --mode insert \cv '__fzf_search_shell_variables'
+        bind --mode insert \e\cl '__fzf_search_git_log'
     end
 end
 

functions/uninstall.fish

@@ -1,9 +1,9 @@
 #!/usr/bin/env fish
 if not set --query fzf_fish_custom_keybindings
     bind --erase --all \cf
-    bind --erase --all \cl
     bind --erase --all \cr
     bind --erase --all \cv
+    bind --erase --all \c\el
 
     set_color --italics cyan
     echo "fzf.fish key kindings removed"