Don't set abbreviations when program doesn't exist

When switching systems, sometimes the alternatives I have set up are
not installed; in those cases, don't cause trouble!

profiles/fish/config.fish

@@ -4,24 +4,37 @@
 # replacement programs.
 
 # make common programs easier to use
-abbr -ga g git
+if type -q git
+   abbr -ga g git
+end
 
 # configure ls and tree replacement
-alias exa='exa -s type' # directories first
-abbr -ga ls exa -x
-abbr -ga ll exa -hl
-abbr -ga la exa -ax
-abbr -ga tree exa -T
+if type -q exa
+   alias exa='exa -s type' # directories first
+   abbr -ga ls exa
+   abbr -ga ll exa -hl
+   abbr -ga la exa -ax
+   abbr -ga tree exa -T
+end
 
 # add abbreviation for cargo
-abbr -ga c cargo
+if type -q cargo
+   abbr -ga c cargo
+end
 
 # configure cat replacement
-alias cat='bat'
-set -x BAT_THEME 'Monokai Extended'
+if type -q bat
+   abbr -ga cat bat
+   set -x BAT_THEME 'Monokai Extended'
+end
 
 # configure find replacement
-abbr -ga find fd
+if type -q fdfind
+   abbr -ga find fdfind
+end
 
 # open files in the default (gui) program
 abbr -ga open xdg-open
+
+# Update path to include custom path directories
+set -x PATH "$PATH:$HOME/.cargo/bin/"