MISC: Improve several things relating to PID lookups (#1594)

findRunningScriptByPid needlessly took a "server" argument. This caused
there to be a "getRunningScriptByPid" version that did *not*, and it was
looping through all servers in order to function, which is needlessly
inefficient.

By removing the parameter and the needless inefficient helper method,
the following changes:
- Many Netscript functions such as isRunning() and getScript() become faster.
- The terminal "tail" command now works by pid regardless of the current
  server. Note that "kill" already worked this way.

I also improved the docs around "tail", since the pid argument wasn't
in the help.

src/Script/ScriptHelpers.ts

@@ -98,12 +98,9 @@ export function findRunningScripts(
   return server.runningScriptMap.get(scriptKey(path, args)) ?? null;
 }
 
-//Returns a RunningScript object matching the pid on the
-//designated server, and false otherwise
-export function findRunningScriptByPid(pid: number, server: BaseServer): RunningScript | null {
+//Returns a RunningScript object with the given pid, or null
+export function findRunningScriptByPid(pid: number): RunningScript | null {
   const ws = workerScripts.get(pid);
-  // Return null if no ws found or if it's on a different server.
   if (!ws) return null;
-  if (ws.scriptRef.server !== server.hostname) return null;
   return ws.scriptRef;
 }