fix punctuation mark

fix typo
Signed-off-by: abejidefemi1@gmail.com <abejidefemi1@gmail.com>

README.md

@@ -16,7 +16,7 @@ from configured targets at given intervals, evaluates rule expressions,
 displays the results, and can trigger alerts if some condition is observed
 to be true.
 
-Prometheus' main distinguishing features as compared to other monitoring systems are:
+Prometheus's main distinguishing features as compared to other monitoring systems are:
 
 - a **multi-dimensional** data model (timeseries defined by metric name and set of key/value dimensions)
 - a **flexible query language** to leverage this dimensionality

docs/storage.md

@@ -51,7 +51,7 @@ For further details on file format, see [TSDB format](https://github.com/prometh
 
 The initial two-hour blocks are eventually compacted into longer blocks in the background.
 
-Compaction will create larger blocks up to 10% of the rention time, or 21 days, whichever is smaller.
+Compaction will create larger blocks up to 10% of the retention time, or 21 days, whichever is smaller.
 
 ## Operational aspects