doc: Clarify how to run codacy-coverage-reporter

The Codacy Coverage Reporter must run on the root of a locally checked
out branch of the Git repository.

Also, it's more explicit to recommend specifying the path to the
coverage report manually since the Coverage Reporter may not find all
coverage report files (for example, if they're in a subdirectory).

Author: Paulo Ribeiro

docs/adding-coverage-to-your-repository.md

@@ -39,15 +39,16 @@ After having coverage reports set up for your repository, you must use Codacy Co
     export CODACY_API_BASE_URL=<your Codacy instance URL>
     ```
 
-1.  Run Codacy Coverage Reporter to upload the coverage results to Codacy.
-
-    The recommended way to do this is using a self-contained script that automatically downloads and runs the most recent version of Codacy Coverage Reporter:
+1.  Run Codacy Coverage Reporter **on the root of the locally checked out branch of your Git repository**, specifying the relative path to the coverage report to upload. For example:
 
     ```bash
-    bash <(curl -Ls https://coverage.codacy.com/get.sh) report
+    bash <(curl -Ls https://coverage.codacy.com/get.sh) report -r report.xml
     ```
 
-    See [alternative ways of running Codacy Coverage Reporter](alternative-ways-of-running-coverage-reporter.md) for other ways of running Codacy Coverage Reporter, such as by installing the binary manually or using a CircleCI Orb or GitHub Action.
+    !!! tip
+        The recommended self-contained script automatically downloads and runs the most recent version of Codacy Coverage Reporter.
+
+        See [alternative ways of running Codacy Coverage Reporter](alternative-ways-of-running-coverage-reporter.md) for other ways of running Codacy Coverage Reporter, such as by installing the binary manually or using a GitHub Action or CircleCI Orb.
 
 1.  Optionally, [add a Codacy badge](https://docs.codacy.com/repositories/badges/) to the README of your repository to display the current code coverage.