MarkDown syntax highlighting, whitespace cleanup

As I mentioned in PR #8704 (**Format of resolution for "The TPM is locked out."**), "ps" does not identify as a syntax highlighting code keyword for PowerShell. The keywords "powershell" or "PowerShell" should be used in the current implementation of GitHub Flavored MarkDown (GFM). The syntax highlighting added in PR PR #8704, "ps" translates to PostScript via one of its filename extensions (.ps, .eps, .epsi, .pfa), whereas PowerShell can only be identified via its filename extensions .ps1, .psd1, .psm1 when not using its dedicated keyword PowerShell/powershell. Secondary IDs like filename extensions are discouraged as long as known keywords exist and are valid.

The Linguist project here on GitHub (https://github.com/github/linguist) for a complete list of syntax highlighting keywords:
- https://github.com/github/linguist/blob/master/lib/linguist/languages.yml
 ("Defines all Languages known to GitHub.")

Proposed changes:
- correct the MarkDown code block syntax highlighting keyword "ps" to "powershell"

Whitespace changes:
- remove redundant end-of-line blanks
- reduce the spacing between metadata and page title from 2 to 1 blank line
- add missing NewLine at end-of-file (last line)

Ticket closure or reference:

ref. #8704

windows/security/information-protection/bitlocker/ts-bitlocker-cannot-encrypt-tpm-issues.md

@@ -16,7 +16,6 @@ ms.date: 10/18/2019
 ms.custom: bitlocker
 ---
 
-
 # BitLocker cannot encrypt a drive: known TPM issues
 
 This article describes common issues that affect the Trusted Platform Module (TPM) and that may prevent BitLocker from encrypting a drive. This article also provides guidance to address these issues.
@@ -38,7 +37,7 @@ To resolve this issue, follow these steps:
 
 1. Open an elevated PowerShell window and run the following script:
 
-   ```ps
+   ```powershell
    $Tpm = Get-WmiObject -class Win32_Tpm -namespace "root\CIMv2\Security\MicrosoftTpm"
    $ConfirmationStatus = $Tpm.GetPhysicalPresenceConfirmationStatus(22).ConfirmationStatus
    if($ConfirmationStatus -ne 4) {$Tpm.SetPhysicalPresenceRequest(22)}
@@ -90,7 +89,7 @@ To verify that you have correctly identified this issue, use one of the followin
 
 1. To review the TPM information for the affected computer, open an elevated Windows PowerShell window and run the following command:
 
-   ```ps
+   ```powershell
    Get-ADComputer -Filter {Name -like "ComputerName"} -Property * | Format-Table name,msTPM-TPMInformationForComputer
    ```
 
@@ -121,7 +120,7 @@ To resolve this issue, follow these steps:
 1. In the script, modify the value of **strPathToDomain** to your domain name.
 1. Open an elevated PowerShell window, and run the following command:
 
-   ```ps
+   ```powershell
    cscript <Path>Add-TPMSelfWriteACE.vbs
    ```