[wic][PATCH] README.md: literal cleanups

[Trevor Woerner <twoerner@gmail.com>]

Using ```bash works in almost all markdown renderers, but unfortunately
does not work on git.yoctoproject.org. Instead it inserts "bash" at the
start of any such literal code block that uses it.

Technically a code block in markdown requires 4 spaces, not 3. Therefore
the "git send-email ..." command would not be offset correctly in most
markdown renderers. Either add another space, or delimit with ``` to
match the other code blocks; I chose the latter.

Signed-off-by: Trevor Woerner <twoerner@gmail.com>
---
 README.md | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 32590195fae1..75229421763c 100644
--- a/README.md
+++ b/README.md
@@ -10,33 +10,33 @@ environment file or folder (generated via `bitbake -c rootfs_wicenv
 ### Using wicenv (one environment file)
 1. Ensure you have a BitBake-generated `<image>.env` file (from `rootfs_wicenv`).
 2. Install locally for development:
-   ```bash
+   ```
    hatch shell
    ```
 3. Run the CLI:
-   ```bash
+   ```
    hatch run wic --vars /path/to/<image>.env --help
    ```
 
 ### Using wicenv (environment folder)
 1. Ensure you have a folder with BitBake-generated `<image>.env` files (from `rootfs_wicenv`).
 2. Install locally for development:
-   ```bash
+   ```
    hatch shell
    ```
 3. Run the CLI:
-   ```bash
+   ```
    hatch run wic --vars /path/to/envfiledir --help
    ```
 
 ### With bitbake
 1. Ensure you have bitbake available in your PATH.
 2. Install locally for development:
-   ```bash
+   ```
    hatch shell
    ```
 3. Run the CLI:
-   ```bash
+   ```
    hatch run wic --help
    ```
 
@@ -63,7 +63,9 @@ recipients.
 
 When generating the patches manually, this will generate what's expected:
 
-   git send-email -M -1 --to yocto-patches@lists.yoctoproject.org --cc twoerner@gmail.com --subject-prefix='wic][PATCH'
+```
+git send-email -M -1 --to yocto-patches@lists.yoctoproject.org --cc twoerner@gmail.com --subject-prefix='wic][PATCH'
+```
 
 Nothing, except running `b4 send` to actually send the patches, needs to be done
 when using [b4](https://b4.docs.kernel.org/).
-- 
2.51.0