Bug 1748845 - Update source-relative links in performance docs, r=firefox-source-docs-reviewers,sylvestre

These were broken since we adopted MyST.

Differential Revision: https://phabricator.services.mozilla.com/D135386

docs/performance/GPU_performance.md

@@ -5,9 +5,8 @@ asynchronous and massively parallel architecture.
 
 ## Tools
 
-PIX - Can do timing of Direct3D calls. Works reasonably well with
-Firefox. See also [Debugging With
-PIX](/en/Debugging_With_PIX "en/Debugging With PIX").
+[PIX](https://devblogs.microsoft.com/pix/introduction/) - Can do
+timing of Direct3D calls. Works reasonably well with Firefox.
 
 NVIDIA PerfHUD - Last I checked required a special build to be used.
 

docs/performance/automated_performance_testing_and_sheriffing.md

@@ -15,7 +15,7 @@ degree):
 -   [Talos](https://wiki.mozilla.org/TestEngineering/Performance/Talos): The main
     performance system, run on virtually every check-in to an
     integration branch
--   [build_metrics](/setup/configuring_build_options.html):
+-   [build_metrics](/setup/configuring_build_options.rst):
     A grab bag of performance metrics generated by the build system
 -   [AreWeFastYet](https://arewefastyet.com/): A generic JavaScript and
     Web benchmarking system

docs/performance/dtrace.md

@@ -5,8 +5,7 @@ be used to profile wakeups. This article provides a light introduction
 to it.
 
 :::
-**Note**: The [power profiling
-overview](/en-US/docs/Mozilla/Performance/Power_profiling_overview) is
+**Note**: The [power profiling overview](power_profiling_overview.md) is
 worth reading at this point if you haven't already. It may make parts
 of this document easier to understand.
 :::
@@ -16,7 +15,7 @@ of this document easier to understand.
 `dtrace` must be invoked as the super-user. A good starting command for
 profiling wakeups is the following.
 
-``` 
+```
 sudo dtrace -n 'mach_kernel::wakeup { @[ustack()] = count(); }' -p $FIREFOX_PID > $OUTPUT_FILE
 ```
 

docs/performance/index.md

@@ -2,13 +2,13 @@
 
 This page explains how optimize the performance the Firefox code base
 
-The [test documentation](../../testing/perfdocs/)
-explains how to test for performance in Firefox. 
-The [profiler documentation](../../tools/profiler/)
-explains how to use the Gecko profiler. 
+The [test documentation](/testing/perfdocs/index.rst)
+explains how to test for performance in Firefox.
+The [profiler documentation](/tools/profiler/index.rst)
+explains how to use the Gecko profiler.
 
 ## General Performance references
-* Tips on generating valid performance metrics by [benchmarking](benchmarking.md)
+* Tips on generating valid performance metrics by [benchmarking](Benchmarking.md)
 * [GPU Performance](GPU_performance.md) Tips for reducing impacts on browser performance in front-end code.
 * [Automated Performance testing and Sheriffing](automated_performance_testing_and_sheriffing.md) Information on automated performance testing and sheriffing at Mozilla.
 * [Performance best practices for Firefox front-end engineers](bestpractices.md) Tips for reducing impacts on browser performance in front-end code.

docs/performance/tools_power_rapl.md

@@ -12,7 +12,7 @@ of this document easier to understand.
 
 ## Invocation
 
-First, do a [standard build of Firefox](../setup/index.html).
+First, do a [standard build of Firefox](/setup/index.rst).
 
 ### Mac