This PR improves the regex example in the tail input plugin and in th…

…e multiline filter example (#1241)

Signed-off-by: RicardoAAD <[email protected]>

pipeline/filters/multiline-stacktrace.md

@@ -110,7 +110,7 @@ This second file defines a multiline parser for the example. Note that a second
     #
     # rules |   state name  | regex pattern                  | next state
     # ------|---------------|--------------------------------------------
-    rule      "start_state"   "/(Dec \d+ \d+\:\d+\:\d+)(.*)/"  "cont"
+    rule      "start_state"   "/([A-Za-z]+ \d+ \d+\:\d+\:\d+)(.*)/"  "cont"
     rule      "cont"          "/^\s+at.*/"                     "cont"
     
 ```

pipeline/inputs/tail.md

@@ -178,7 +178,7 @@ In the case above we can use the following parser, that extracts the Time as `ti
 [PARSER]
     Name multiline
     Format regex
-    Regex /(?<time>Dec \d+ \d+\:\d+\:\d+)(?<message>.*)/
+    Regex /(?<time>[A-Za-z]+ \d+ \d+\:\d+\:\d+)(?<message>.*)/
     Time_Key  time
     Time_Format %b %d %H:%M:%S
 ```
@@ -190,7 +190,7 @@ If we want to further parse the entire event we can add additional parsers with
 [PARSER]
     Name multiline
     Format regex
-    Regex /(?<time>Dec \d+ \d+\:\d+\:\d+)(?<message>.*)/
+    Regex /(?<time>[A-Za-z]+ \d+ \d+\:\d+\:\d+)(?<message>.*)/
     Time_Key  time
     Time_Format %b %d %H:%M:%S