fix(backends/lean): extract more keywords from `lstlean.tex`

Taken from
https://github.com/leanprover/lean4/blob/master/doc/latex/lstlean.tex#L33
and
https://github.com/leanprover/lean4/blob/master/doc/latex/lstlean.tex#L36-L43.

This will not extract the tactics.

Signed-off-by: Ryan Lahfa <ryan.lahfa@inria.fr>

1 files changed, 2 insertions, 0 deletions

diff --git a/compiler/ExtractBase.ml b/compiler/ExtractBase.ml
index ddffb1c2..e30c4b36 100644
--- a/compiler/ExtractBase.ml
+++ b/compiler/ExtractBase.ml
@@ -916,6 +916,8 @@ let keywords () =
     | Lean ->
         [
           "Pi";
+          "Prop";
+          "Sort";
           "Type";
           "abbrev";
           "alias";