Bjolang's raw strings are strings

Bjolang reads """...""" as a raw string: three or more quotes open it, the
same number close it, and nothing in it is an escape. The grammar has a
string.quoted.triple.bjolang scope for it, so quotes inside one stay inside,
and one over several lines is a string on every line. tests/demo.bjo checks
both, and passes.

🤖 Generated with [ECA](https://eca.dev) (anthropic/claude-opus-5-5)

Co-Authored-By: eca-agent <git@eca.dev>

grammars/bjolang/syntaxes/bjolang.tmLanguage.json

@@ -26,6 +26,9 @@
         {
           "include": "#interpolated-string"
         },
+        {
+          "include": "#raw-string"
+        },
         {
           "include": "#string"
         },
@@ -107,6 +110,22 @@
         }
       ]
     },
+    "raw-string": {
+      "comment": "\"\"\"...\"\"\": three or more quotes open it, the same number close it, and nothing in it is an escape.",
+      "begin": "(\"{3,})",
+      "beginCaptures": {
+        "0": {
+          "name": "punctuation.definition.string.begin.bjolang"
+        }
+      },
+      "end": "(?<!\")\\1(?!\")",
+      "endCaptures": {
+        "0": {
+          "name": "punctuation.definition.string.end.bjolang"
+        }
+      },
+      "name": "string.quoted.triple.bjolang"
+    },
     "string": {
       "begin": "\"",
       "beginCaptures": {