docs: Fix Markdown rendering issues

- Fix rendering issues of multi-line HTML comments (license headers)
- Fix rendering issues of footnotes

Change-Id: I06c8ad3454a62187e9d527df62560b897ec478f4
Signed-off-by: David Vincze <david.vincze@linaro.org>
diff --git a/docs/PORTING.md b/docs/PORTING.md
index bf68d6d..61a4f8d 100644
--- a/docs/PORTING.md
+++ b/docs/PORTING.md
@@ -144,7 +144,7 @@
 needs to provide this pair of function.
 
 To configure the what functions are called when allocating/deallocating
-memory `mbed TLS` uses the following call [^cite1]:
+memory `mbed TLS` uses the following call [^1]:
 
 ```
 int mbedtls_platform_set_calloc_free (void *(*calloc_func)(size_t, size_t),
@@ -155,4 +155,4 @@
 can be used directly here, otherwise create new functions that glue to
 your `calloc/free` implementations.
 
-[^cite1]```https://tls.mbed.org/api/platform_8h.html```
+[^1]: ```https://tls.mbed.org/api/platform_8h.html```