Fix two protocol-less links

You'd need a protocol droid to figure out what protocol to use for
those, and link checkers typically lack such help.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

content/good-commits.md

@@ -25,7 +25,7 @@ Also important:
 - [Sign off](https://github.com/git/git/blob/v2.8.1/Documentation/SubmittingPatches#L234-L286) on your change (i.e. state that you release this patch as Open Source, if applicable with your employer's consent).
 - Format the commit message to wrap at 76 columns per line.
 
-A good example for a commit message is [git-for-windows/build-extra@a64fe115](github.com/git-for-windows/build-extra/commit/a64fe115d901cab775c881bd1624218ac28de4d4):
+A good example for a commit message is [git-for-windows/build-extra@a64fe115](https://github.com/git-for-windows/build-extra/commit/a64fe115d901cab775c881bd1624218ac28de4d4):
 
 ```
 Install 7-Zip without confirmation if it is missing

content/snapshot-builds.md

@@ -11,4 +11,4 @@ To allow users to help verifying that "always-releasable state", as well as to a
 
 Those snapshot releases are considered robust. They are built using [the exact same Azure Pipeline](https://dev.azure.com/git-for-windows/git/_build?definitionId=34&_a=summary) that also builds official Git for Windows versions (as well as the `-rc` pre-releases leading up to every major version). Snapshot versions come in the same flavors as full Git for Windows versions: 32-bit and 64-bit, installers, portable Gits, MinGits.
 
-Snapshot versions are signed the same way as full Git for Windows versions, too. Apart from the version number and from the fact that they are not uploaded as [full GitHub Releases](github.com/git-for-windows/git/releases), they are pretty much indistinguishable from official Git for Windows versions.
+Snapshot versions are signed the same way as full Git for Windows versions, too. Apart from the version number and from the fact that they are not uploaded as [full GitHub Releases](https://github.com/git-for-windows/git/releases), they are pretty much indistinguishable from official Git for Windows versions.