[coq] Untabify the whole ML codebase.

We also remove trailing whitespace.

Script used:

```bash
for i in `find . -name '*.ml' -or -name '*.mli' -or -name '*.mlg'`; do expand -i "$i" | sponge "$i"; sed -e's/[[:space:]]*$//' -i.bak "$i"; done
```

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/declarations.ml b/kernel/declarations.ml
index 44676c9da5..9fd10b32e6 100644
--- a/kernel/declarations.ml
+++ b/kernel/declarations.ml
@@ -25,7 +25,7 @@ type engagement = set_predicativity
     and constants hiding inductives are implicitly polymorphic when
     applied to parameters, on the universes appearing in the whnf of
     their parameters and their conclusion, in a template style.
-    
+
     In truly universe polymorphic mode, we always use RegularArity.
 *)
 
@@ -34,7 +34,7 @@ type template_arity = {
   template_level : Univ.Universe.t;
 }
 
-type ('a, 'b) declaration_arity = 
+type ('a, 'b) declaration_arity =
   | RegularArity of 'a
   | TemplateArity of 'b