Don't require statement terminator at EOF

Fixes #15

corpus/programs.txt

@@ -50,3 +50,12 @@ echo 1 \ 2 \ 3
 ---
 
 (program (command (command_name (word)) (word) (word) (word)))
+
+====================================
+Files without trailing terminators
+====================================
+
+echo hi
+---
+
+(program (command (command_name (word)) (word)))

grammar.js

@@ -47,7 +47,7 @@ module.exports = grammar({
   word: $ => $.word,
 
   rules: {
-    program: $ => repeat($._terminated_statement),
+    program: $ => optional($._statements),
 
     _terminated_statement: $ => seq(
       $._statement,

script/known-failures.txt

@@ -3,7 +3,6 @@ examples/bash-it/plugins/available/extract.plugin.bash
 examples/bash-it/plugins/available/go.plugin.bash
 examples/bash-it/install.sh
 examples/bash-it/completion/available/go.completion.bash
-examples/bash-it/completion/available/maven.completion.bash
 examples/bash-it/completion/available/svn.completion.bash
 examples/bash-it/completion/available/docker-compose.completion.bash
 examples/bash-it/completion/available/jboss7.completion.bash
@@ -20,7 +19,6 @@ examples/bash-it/completion/available/vault.completion.bash
 examples/bash-it/completion/available/docker.completion.bash
 examples/bash-it/completion/available/tmux.completion.bash
 examples/bash-it/completion/available/apm.completion.bash
-examples/bash-it/completion/available/git_flow.completion.bash
 examples/bash-it/lib/preexec.bash
 examples/bash-it/lib/composure.bash
 examples/bash-it/test_lib/bats-support/src/lang.bash
@@ -34,6 +32,5 @@ examples/bash-it/themes/powerline/powerline.base.bash
 examples/bash-it/themes/base.theme.bash
 examples/bash-it/themes/brainy/brainy.theme.bash
 examples/bash-it/themes/nwinkler_random_colors/nwinkler_random_colors.theme.bash
-examples/bash-it/themes/mbriggs/mbriggs.theme.bash
 examples/bash-it/themes/kitsune/kitsune.theme.bash
 examples/bash-it/themes/doubletime/doubletime.theme.bash

src/grammar.json

@@ -3,11 +3,16 @@
   "word": "word",
   "rules": {
     "program": {
-      "type": "REPEAT",
-      "content": {
-        "type": "SYMBOL",
-        "name": "_terminated_statement"
-      }
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "_statements"
+        },
+        {
+          "type": "BLANK"
+        }
+      ]
     },
     "_terminated_statement": {
       "type": "SEQ",