fix(compiler): markup lexer should not capture quotes in attribute value (#28055)

When tokenizing markup (e.g. HTML) element attributes
can have quoted or unquoted values (e.g. `a=b` or `a="b"`).
The `ATTR_VALUE` tokens were capturing the quotes, which
was inconsistent and also affected source-mapping.

Now the tokenizer captures additional `ATTR_QUOTE` tokens,
which the HTML related parsers understand and factor into their
token parsing.

PR Close #28055

packages/language-service/src/locate_symbol.ts

@@ -33,7 +33,7 @@ export function locateSymbol(info: TemplateInfo): SymbolInfo|undefined {
           const dinfo = diagnosticInfoFromTemplateInfo(info);
           const scope = getExpressionScope(dinfo, path, inEvent);
           if (attribute.valueSpan) {
-            const expressionOffset = attribute.valueSpan.start.offset + 1;
+            const expressionOffset = attribute.valueSpan.start.offset;
             const result = getExpressionSymbol(
                 scope, ast, templatePosition - expressionOffset, info.template.query);
             if (result) {