Bump version to 6.0 (#62162)

src/compiler/corePublic.ts

@@ -1,6 +1,6 @@
 // WARNING: The script `configurePrerelease.ts` uses a regexp to parse out these values.
 // If changing the text in this section, be sure to test `configurePrerelease` too.
-export const versionMajorMinor = "5.9";
+export const versionMajorMinor = "6.0";
 // The following is baselined as a literal template type without intervention
 /** The version of the TypeScript compiler release */
 export const version: string = `${versionMajorMinor}.0-dev`;