Keep TypeScript division expressions out of regex highlighting

[justadityaraj]

Context

TypeScript's regular-expression rule cannot distinguish regex literals from division expressions with the syntax highlighter's regular-expression engine. It therefore treats text between division operators, such as / 2.0, height /, as a regex constant. JavaScript already disables the same ambiguous rule, and the maintainer accepted that fallback for TypeScript in #3874.

Changes

• Disable the ambiguous TypeScript regex-literal rule, matching the existing JavaScript behavior.
• Add a regression that rejects constant highlighting in a chained division expression.

User impact

Ordinary TypeScript division expressions keep their correct token colors instead of having the operands between slash characters displayed as a regex literal. Regex literals remain unclassified rather than risking false highlighting across unrelated code.

Verification

• Regression on clean master — failed with division highlighted as constant.
• go test ./runtime -run TestTypeScriptDivisionIsNotRegexp -count=10 — passed.
• go test ./... -count=1 — passed.
• go generate ./runtime — passed with no additional tracked changes.
• go build ./cmd/micro — passed.
• git diff --check — passed.
• go vet ./... — retains the existing unkeyed-literal and copied-lock warnings reproduced on clean master.
• Micro's tcell simulation screen reproduced the incorrect regex coloring on clean master and the corrected division coloring after the change.

Before	After

Fixes #3874