docs: update stale repo URLs and build recipe

The project moved to meshcore-dev/meshcore, but two links still pointed at
ripplebiz/MeshCore: the GitHub Issues link in README and the git clone in the
FAQ build instructions.

Also fixes the FAQ build recipe:
- `pio run -e RAK_4631_Repeater` does not exist; the env is spelled
  RAK_4631_repeater (variants/rak4631/platformio.ini:40).
- LORA_FREQ was given as 867.5; the default in [arduino_base] is 869.618
  (platformio.ini:29). Reworded to point at the flag rather than a value that
  drifts with the default preset.
- Renamed the venv so it no longer collides with the cloned directory name.

And one more env-name casing slip in the Raspberry Pi flashing instructions:
`Heltec_V3_companion_radio_ble` should be `Heltec_v3_...`. Release artifacts are
named directly from the env name (build.sh:147), and the two neighbouring
examples in the same block already use the lowercase spelling.

README.md

@@ -123,6 +123,6 @@ There are a number of fairly major features in the pipeline, with no particular
 
 ## 📞 Get Support
 
-- Report bugs and request features on the [GitHub Issues](https://github.com/ripplebiz/MeshCore/issues) page.
+- Report bugs and request features on the [GitHub Issues](https://github.com/meshcore-dev/meshcore/issues) page.
 - Find additional guides and components on [my site](https://buymeacoffee.com/ripplebiz).
 - Join [MeshCore Discord](https://meshcore.gg) to chat with the developers and get help from the community.

docs/faq.md

@@ -537,18 +537,18 @@ Mac: python3 should be already installed.
 
 Then it should be the same for all platforms:
 ```
-python3 -m venv meshcore
-cd meshcore && source bin/activate
+python3 -m venv meshcore-venv
+cd meshcore-venv && source bin/activate
 pip install -U platformio
-git clone https://github.com/ripplebiz/MeshCore.git
-cd MeshCore
+git clone https://github.com/meshcore-dev/meshcore.git
+cd meshcore
 ```
-open platformio.ini and in `[arduino_base]` edit the `LORA_FREQ=867.5`
-save, then run:
+open platformio.ini and in `[arduino_base]` edit `LORA_FREQ` (it defaults to
+`869.618`) to the frequency for your region, save, then run:
 ```
-pio run -e RAK_4631_Repeater
+pio run -e RAK_4631_repeater
 ```
-then you'll find `firmware.zip` in `.pio/build/RAK_4631_Repeater`
+then you'll find `firmware.zip` in `.pio/build/RAK_4631_repeater`
 
 ### 5.10. Q: Are there other MeshCore related open source projects?
 
@@ -592,7 +592,7 @@ For ESP-based devices (e.g. Heltec V3) you need:
 1. Download the firmware file from <https://flasher.meshcore.io>.
     - Go to the website in a browser and find the section that has the firmware you need.
     - Click the Download button, right-click on the file you need, for example:
-        - `Heltec_V3_companion_radio_ble-v1.7.1-165fb33.bin`
+        - `Heltec_v3_companion_radio_ble-v1.7.1-165fb33.bin`
             - Non-merged bin keeps the existing Bluetooth pairing database.
         - `Heltec_v3_companion_radio_usb-v1.7.1-165fb33-merged.bin`
             - Merged bin overwrites everything including the bootloader and existing Bluetooth pairing database, but keeps configurations.