refactor: replace deprecated String.prototype.substr()

.substr() is deprecated so we replace it with .slice() which works similarily but isn't deprecated
Signed-off-by: Tobias Speicher <rootcommander@gmail.com>

Author: CommanderRoot

extensions/ql-vscode/src/cli.ts

@@ -1106,8 +1106,8 @@ class SplitBuffer {
     while (this.searchIndex <= (this.buffer.length - this.maxSeparatorLength)) {
       for (const separator of this.separators) {
         if (SplitBuffer.startsWith(this.buffer, separator, this.searchIndex)) {
-          const line = this.buffer.substr(0, this.searchIndex);
-          this.buffer = this.buffer.substr(this.searchIndex + separator.length);
+          const line = this.buffer.slice(0, this.searchIndex);
+          this.buffer = this.buffer.slice(this.searchIndex + separator.length);
           this.searchIndex = 0;
           return line;
         }

extensions/ql-vscode/src/test-adapter.ts

@@ -76,7 +76,7 @@ export class QLTestAdapterFactory extends DisposableObject {
  * @param ext The new extension, including the `.`.
  */
 function changeExtension(p: string, ext: string): string {
-  return p.substr(0, p.length - path.extname(p).length) + ext;
+  return p.slice(0, -path.extname(p).length) + ext;
 }
 
 /**