parsers: Add Fortran parser

Fixes: https://github.com/nvim-treesitter/nvim-treesitter/issues/1194

Refs:
- https://nvim-treesitter.zulipchat.com/#narrow/stream/252271-general/topic/Meeting.20everyone/near/219174700

lua/nvim-treesitter/parsers.lua

@@ -541,6 +541,14 @@ list.zig = {
   maintainers = { "@Himujjal" }
 }
 
+list.fortran = {
+  install_info = {
+    url = "https://github.com/stadelmanma/tree-sitter-fortran",
+    files = { "src/parser.c", "src/scanner.cc", },
+    requires_generate_from_grammar = true,
+  },
+}
+
 local M = {
   list = list
 }