Work on error messages

Signed-off-by: Marcel Müller <neikos@neikos.email>

tests/errors/invalid_controls.2-ast.snap

@@ -2,31 +2,50 @@
 source: tests/file_tests.rs
 expression: ast
 info:
-  input: "{{ if }} {{ end }}\n{{ if if }} {{ end }}\n{{ if if }} {{ for foo in bar }} {{ end }} {{ end }}\n{{ for in bar }} {{ end }}\n{{ for blah bar }} {{ end }}\n{{ else }}"
+  input: "{{ if }} {{ end }}\n{{ if if }} {{ end }}\n{{ if if }} {{ for foo in bar }} {{ end }} {{ end }}\n{{ for in bar }} {{ end }}\n{{ for blah bar }} {{ end }}\n{{ for blah}} {{ end }}\n{{ else }}"
   context: {}
 ---
 error: Expected an expression after 'if'
   ╭▸ 
 1 │ {{ if }} {{ end }}
-  │    ━━
-  ╰╴
+  ╰╴   ━━
+
 error: Expected an expression after 'if'
   ╭▸ 
 2 │ {{ if if }} {{ end }}
   ╰╴      ━━
+
 error: Expected an expression after 'if'
   ╭▸ 
 3 │ {{ if if }} {{ for foo in bar }} {{ end }} {{ end }}
   ╰╴      ━━
-error: Expected identifier here
+
+error: Missing ident here
   ╭▸ 
 4 │ {{ for in bar }} {{ end }}
   ╰╴       ━━━━━━
-error: Missing `in` in `for _ in <expr>`
+
+error: Missing `in` in `for .. in ` loop
   ╭▸ 
 5 │ {{ for blah bar }} {{ end }}
-  ╰╴       ━━━━━━━━
-error: An error occurred while producing an Ast
+  │        ━━━━━━━━
+  ╰╴
+note: Try adding it
+  ╭╴
+5 │ {{ for blah in bar }} {{ end }}
+  ╰╴            ++
+
+error: Missing `in` in `for .. in ` loop
   ╭▸ 
-6 │ {{ else }}
-  ╰╴   ━━━━━━━
+6 │ {{ for blah}} {{ end }}
+  │        ━━━━
+  ╰╴
+note: Try adding it
+  ╭╴
+6 │ {{ for blah in}} {{ end }}
+  ╰╴            ++
+
+error: Unexpected keyword
+  ╭▸ 
+7 │ {{ else }}
+  ╰╴   ━━━━