added more markdown tags to docs/internals/versions.md for better readability

docs/internals/versions.md

@@ -4,17 +4,21 @@ Yii version numbering
 Releases
 --------
 
+```
 A.B.C
+```
 
-A = For Yii2 it's always 2.
-B = Major version. Non-BC changes with upgrade instructions.
-C = BC changes and additions.
+- A = For Yii2 it's always 2.
+- B = Major version. Non-BC changes with upgrade instructions.
+- C = BC changes and additions.
 
 Release candidates
 ------------------
 
+```
 A.B.C-rc
 A.B.C-rc2
+```
 
 This is when we want to do a release candidate. RC number increments till we're getting a stable release with no
 critical bugs and backwards incompatibility reports.
@@ -22,14 +26,18 @@ critical bugs and backwards incompatibility reports.
 Alphas and betas
 ----------------
 
+```
 A.B.C-alpha
 A.B.C-alpha2
+```
 
 Alphas are unstable versions where significant bugs may and probably do exist. API isn't fixed yet and may be changed
 significantly. `alpha2` etc. may or may not be released based on overall stability of code and API.
 
+```
 A.B.C-beta
 A.B.C-beta2
+```
 
 Beta is more or less stable with less bugs and API instability than alphas. There still could be changes in API but
 there should be a significant reason for it.