Document line-significance limitations in the Pico-8 Lua grammar

PICO-8's shorthand `if (cond) stmt [else stmt]` is line-bounded, but
tree-sitter has no built-in newline awareness. Without an external
scanner ( the same mechanism tree-sitter-python uses for INDENT /
DEDENT / NEWLINE ), the grammar greedily binds `else` to the nearest
`if` and takes only one consequence statement for the shorthand body.
Token classification is unaffected, so syntax highlighting renders
identically to a correct parse; only auto-indent and semantic
selection are subtly off, in a code pattern that is uncommon in real
PICO-8 code.

New `grammars/pico-8-lua/KNOWN_LIMITATIONS.md` walks through both
incorrect cases ( the dangling-else mis-bind and the multi-statement
shorthand body ), tabulates which Zed features are and aren't
affected, and sketches the fix. README cross-links it from the
"Known limitations" block and adds it as a prerequisite to the v0.3
LSP work.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -10,3 +10,6 @@ build/
 .tree-sitter/
 grammars/p8_cart/
 grammars/pico8_lua/
+
+# scratch directory for stuff to show an AI agent or reference in the IDE
+.local/