Fix hjson files that *should* not use commas (esl-epfl#552)

The Hjson format specification (https://hjson.github.io/syntax.html)
also discourages the use of trailing commas at the end of a line,
which are harmless (valid) but superfluous and confusing:

> You should omit optional commas to make your data more readable.

It has been decided that adopting this style will be less confusing
and avoid possible repetitions of issue esl-epfl#552 in the future.

This commit removes all the trailing commas from hjson files,
after a meticulous process to verify that none of these trailing commas
had a specific meaning; such as in this hypothetical scenario:
```
    description: '''This is the description's first line,
                    which has a trailing comma.'''
```

configs/ci.hjson

@@ -1,5 +1,5 @@
 {
-    bus_type: "onetoM",
+    bus_type: "onetoM"
     ram_banks: {
         code_and_data: {
             num: 6
@@ -14,7 +14,7 @@
             start: 0
             #minimum size for freeRTOS and clang
             size: 0x00000D800
-        },
+        }
         {
             name: data
             start: 0x00000D800

configs/example_interleaved.hjson

@@ -1,5 +1,5 @@
 {
-    bus_type: "NtoM",
+    bus_type: "NtoM"
     ram_banks: {
         code_and_data: {
             sizes: 64
@@ -31,7 +31,7 @@
             start: 0
             // minimum size for freeRTOS and clang
             size: 0x00000C800
-        },
+        }
         {
             name: data
             start: 0x00000C800

configs/general.hjson

@@ -1,6 +1,6 @@
 {
     ram_address: 0
-    bus_type: "onetoM",
+    bus_type: "onetoM"
     ram_banks: {
         code_and_data: {
             num: 2
@@ -15,7 +15,7 @@
             start: 0
             #minimum size for freeRTOS and clang
             size: 0x00000C800
-        },
+        }
         {
             name: data
             start: 0x00000C800

configs/testall.hjson

@@ -1,5 +1,5 @@
 {
-    bus_type: "onetoM",
+    bus_type: "onetoM"
     ram_banks: {
         code_and_data: {
             num: 3
@@ -14,7 +14,7 @@
             start: 0
             #minimum size for freeRTOS and clang
             size: 0x00000D800
-        },
+        }
         {
             name: data
             start: 0x00000D800

docs/source/Configuration/Configuration.rst

@@ -92,7 +92,7 @@ The other name can be used in code with a `.xheep_` prefix, like in `example_mat
 
     {
         ram_address: 0
-        bus_type: "onetoM",
+        bus_type: "onetoM"
         ram_banks: {
             code_and_data: {
                 num: 2

docs/source/How_to/IntegratePeripheral.md

@@ -85,17 +85,17 @@ b. The module `xilinx_core_v_mini_mcu_wrapper` should be modified as follows:
 +    inout logic [X-1:0] gpio_io,
 ```
 
-c. The pads configuration (pad_cfg.json) must be adapted as well:
+c. The pads configuration (pad_cfg.hjson) must be adapted as well:
 
 ```diff
          gpio: {
--            num: <N>,
-+            num: <N-D>,
-             num_offset: 0, #first gpio is gpio0
+-            num: <N>
++            num: <N-D>
+             num_offset: 0 # first gpio is gpio0
              type: inout
          },
 +        pdm2pcm_pdm: {
-+            num: 1,
++            num: 1
 +            type: inout
 +            mux: {
 +                <peripheral_io>: {
@@ -237,9 +237,9 @@ reg2hw.register.q        // Data to be read from a register
 
 ```
     { window: {
-        name: "RX_WINDOW_NAME",
-        items: "1",
-        validbits: "32",
+        name: "RX_WINDOW_NAME"
+        items: "1"
+        validbits: "32"
         desc: '''Window purpose description'''
         swaccess: "ro"
       }
@@ -314,10 +314,10 @@ If the GPIOs usage has changed, the testbench must be adapted as follows:
 ```
 
 ## Add an interrupt
-You must register the interrupt in the MCU configuration `mcu_cfg.json`.
+You must register the interrupt in the MCU configuration `mcu_cfg.hjson`.
 ```diff
     interrupts: {
-        number: 64, // Do not change this number!
+        number: 64 // Do not change this number!
         list: {
           ...
 +          <interrupt identifier>: <interrupt num>

docs/source/How_to/eXtendingHEEP.md

@@ -38,15 +38,15 @@ In order to vendorize `X-HEEP` create inside your repository's base directory (`
 // SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
 
 {
-  name: "esl_epfl_x_heep",
-  target_dir: "esl_epfl_x_heep",
+  name: "esl_epfl_x_heep"
+  target_dir: "esl_epfl_x_heep"
 
   upstream: {
-    url: "https://github.com/esl-epfl/x-heep.git",
-    rev: "main",
+    url: "https://github.com/esl-epfl/x-heep.git"
+    rev: "main"
   },
 
-  patch_dir: "patches/esl_epfl_x_heep",
+  patch_dir: "patches/esl_epfl_x_heep"
 
   exclude_from_upstream: [
     ".github",