[Vendor] blevesearch v0.8.1 -> v1.0.7 (#11360)

* Update blevesearch v0.8.1 -> v1.0.7

* make vendor

Co-authored-by: zeripath <art27@cantab.net>

vendor/github.com/blevesearch/snowballstem/README.md

@@ -0,0 +1,66 @@
+# snowballstem
+
+This repository contains the Go stemmers generated by the [Snowball](https://github.com/snowballstem/snowball) project.  They are maintained outside of the core bleve package so that they may be more easily be reused in other contexts.
+
+## Usage
+
+All these stemmers export a single `Stem()` method which operates on a snowball `Env` structure.  The `Env` structure maintains all state for the stemmer.  A new `Env` is created to point at an initial string.  After stemming, the results of the `Stem()` operation can be retrieved using the `Current()` method.  The `Env` structure can be reused for subsequent calls by using the `SetCurrent()` method.
+
+## Example
+
+```
+package main
+
+import (
+	"fmt"
+
+	"github.com/blevesearch/snowballstem"
+	"github.com/blevesearch/snowballstem/english"
+)
+
+func main() {
+
+	// words to stem
+	words := []string{
+		"running",
+		"jumping",
+	}
+
+	// build new environment
+	env := snowballstem.NewEnv("")
+
+	for _, word := range words {
+		// set up environment for word
+		env.SetCurrent(word)
+		// invoke stemmer
+		english.Stem(env)
+		// print results
+		fmt.Printf("%s stemmed to %s\n", word, env.Current())
+	}
+}
+```
+Produces Output:
+```
+$ ./snowtest
+running stemmed to run
+jumping stemmed to jump
+```
+
+## Testing
+
+The test harness for these stemmers is hosted in the main [Snowball](https://github.com/snowballstem/snowball) repository.  There are functional tests built around the separate [snowballstem-data](https://github.com/snowballstem/snowball-data) repository, and there is support for fuzz-testing the stemmers there as well.
+
+## Generating the Stemmers
+
+```
+$ export SNOWBALL=/path/to/github.com/snowballstem/snowball/after/snowball/built
+$ go generate
+```
+
+## Updated the Go Generate Commands
+
+A simple tool is provided to automate these from the snowball algorithms directory:
+
+```
+$ go run gengen.go /path/to/github.com/snowballstem/snowball/algorithms
+```