Run fish_indent on all our fish scripts

It's now good enough to do so.

We don't allow grid-alignment:

```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z              -a '(something)'
```

becomes

```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z -a '(something)'
```

It's just more trouble than it is worth.

The one part I'd change:

We align and/or'd parts of an if-condition with the in-block code:

```fish
if true
   and false
    dosomething
end
```

becomes

```fish
if true
    and false
    dosomething
end
```

but it's not used terribly much and if we ever fix it we can just
reindent.

tests/checks/variable-assignment.fish

@@ -58,13 +58,20 @@ xPATH={/usr,}/bin sh -c 'echo $xPATH'
 yPATH=/usr/bin:/bin count $yPATH
 
 # CHECK: b
-a=b begin; true | echo $a; end
+a=b begin
+    true | echo $a
+end
 
 # CHECK: b
-a=b if true; echo $a; end
+a=b if true
+    echo $a
+end
 
 # CHECK: b
-a=b switch x; case x; echo $a; end
+a=b switch x
+    case x
+        echo $a
+end
 
 complete -c x --erase
 complete -c x -xa arg